fix(i18n): require each locale's plural forms in i18n:check

Lithuanian lacked _few forms, so counts like 2 fell back to English.
Add them, fix _other wording for 10+, and update stale docs and comments.

docs/TRANSLATING.md

@@ -31,16 +31,18 @@ To improve an existing language, edit its file the same way; the commit type is
 
 ## Plurals
 
-Text that depends on a number has one key per plural form, ending in `_one`, `_few`, `_many` or `_other`:
+Text that depends on a number has one key per plural form, ending in `_zero`, `_one`, `_two`, `_few`, `_many`
+or `_other`:
 
 ```json
 "minutesAgo_one": "{{count}} minute ago",
 "minutesAgo_other": "{{count}} minutes ago"
 ```
 
-Use the forms your language needs, which aren't always English's: Lithuanian, for example, adds `_few`. Check your
-language in the [Unicode plural rules](https://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html)
-and add or drop forms to match.
+Use the forms your language needs, which aren't always English's: Lithuanian, for example, adds `_few`, and Arabic
+and Welsh also use `_zero` and `_two`. Check your language in the
+[Unicode plural rules](https://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html) and add or
+drop forms to match; `i18n:check` below lists any form your language is missing.
 
 ## Check your translation
 

frontend/scripts/i18n-check.mjs

@@ -1,5 +1,5 @@
 // Lists each locale's keys missing from, or no longer in, en.json: `npm run i18n:check [code]`.
-// Plural forms (key_one, key_few, ...) count as one key, since languages need different ones.
+// A plural key (key_one, key_other, ...) needs every form the locale uses for whole-number counts.
 import { readdirSync, readFileSync } from "node:fs";
 
 const dir = new URL("../src/i18n/locales/", import.meta.url);
@@ -7,12 +7,25 @@ const PLURAL = /_(zero|one|two|few|many|other)$/;
 
 function keys(node, prefix = "") {
   return Object.entries(node).flatMap(([key, value]) =>
-    value && typeof value === "object" ? keys(value, `${prefix}${key}.`) : [`${prefix}${key}`.replace(PLURAL, "")],
+    value && typeof value === "object" ? keys(value, `${prefix}${key}.`) : [`${prefix}${key}`],
   );
 }
 
-const read = (code) => new Set(keys(JSON.parse(readFileSync(new URL(`${code}.json`, dir), "utf8"))));
-const en = read("en");
+const read = (code) => keys(JSON.parse(readFileSync(new URL(`${code}.json`, dir), "utf8")));
+
+// Fractional-only forms (Lithuanian `many`) are left out: counts here are whole numbers.
+function pluralForms(code) {
+  const rules = new Intl.PluralRules(code);
+  return new Set(Array.from({ length: 1000 }, (_, n) => rules.select(n)));
+}
+
+const plurals = new Set();
+const plain = [];
+for (const key of read("en")) {
+  if (PLURAL.test(key)) plurals.add(key.replace(PLURAL, ""));
+  else plain.push(key);
+}
+
 const only = process.argv[2];
 const codes = readdirSync(dir)
   .filter((file) => file.endsWith(".json") && file !== "en.json")
@@ -25,7 +38,10 @@ if (only && codes.length === 0) {
 }
 
 for (const code of codes) {
-  const locale = read(code);
+  const forms = [...pluralForms(code)];
+  const en = new Set([...plain, ...[...plurals].flatMap((base) => forms.map((form) => `${base}_${form}`))]);
+  // Extra plural forms a translator added (such as `_many`) aren't stale, just unused for whole numbers.
+  const locale = new Set(read(code).filter((key) => en.has(key) || !plurals.has(key.replace(PLURAL, ""))));
   const missing = [...en].filter((key) => !locale.has(key));
   const stale = [...locale].filter((key) => !en.has(key));
   const done = Math.floor(((en.size - missing.length) / en.size) * 100);

frontend/src/i18n/locales/lt.json

@@ -287,10 +287,13 @@
       "viewSource": "Žiūrėti šaltinį",
       "justNow": "Ką tik",
       "minutesAgo_one": "prieš {{count}} minutę",
+      "minutesAgo_few": "prieš {{count}} minutes",
       "minutesAgo_other": "prieš {{count}} minučių",
       "hoursAgo_one": "prieš {{count}} valandą",
+      "hoursAgo_few": "prieš {{count}} valandas",
       "hoursAgo_other": "prieš {{count}} valandų",
       "daysAgo_one": "prieš {{count}} dieną",
+      "daysAgo_few": "prieš {{count}} dienas",
       "daysAgo_other": "prieš {{count}} dienų",
       "clearAll": "Išvalyti viską",
       "clearAllConfirm": "Ištrinti visus pranešimus? To nebus galima atšaukti.",
@@ -320,7 +323,8 @@
       "sectionCollections": "Kolekcijos",
       "sectionTags": "Žymos",
       "modelCount_one": "{{count}} modelis",
-      "modelCount_other": "{{count}} modeliai",
+      "modelCount_few": "{{count}} modeliai",
+      "modelCount_other": "{{count}} modelių",
       "sectionRecent": "Neseniai",
       "sectionCommands": "Komandos",
       "open": "Atidaryti",
@@ -1085,14 +1089,19 @@
         "approx": "≈ {{value}}",
         "units": {
           "minutes_one": "{{count}} minutė",
+          "minutes_few": "{{count}} minutės",
           "minutes_other": "{{count}} minučių",
           "hours_one": "{{count}} valanda",
+          "hours_few": "{{count}} valandos",
           "hours_other": "{{count}} valandų",
           "days_one": "{{count}} diena",
+          "days_few": "{{count}} dienos",
           "days_other": "{{count}} dienų",
           "weeks_one": "{{count}} savaitė",
+          "weeks_few": "{{count}} savaitės",
           "weeks_other": "{{count}} savaičių",
           "months_one": "{{count}} mėnuo",
+          "months_few": "{{count}} mėnesiai",
           "months_other": "{{count}} mėnesių"
         },
         "save": "Išsaugoti",
@@ -2822,7 +2831,8 @@
       "card": {
         "empty": "Kol kas nėra modelių",
         "itemCount_one": "{{count}} modelis",
-        "itemCount_other": "{{count}} modeliai"
+        "itemCount_few": "{{count}} modeliai",
+        "itemCount_other": "{{count}} modelių"
       },
       "form": {
         "createTitle": "Nauja kolekcija",
@@ -2998,9 +3008,11 @@
     "downloadZip": {
       "loading": "Skaičiuojama…",
       "summary_one": "{{count}} modelis (~{{size}})",
-      "summary_other": "{{count}} modeliai (~{{size}})",
+      "summary_few": "{{count}} modeliai (~{{size}})",
+      "summary_other": "{{count}} modelių (~{{size}})",
       "summaryNoSize_one": "{{count}} modelis",
-      "summaryNoSize_other": "{{count}} modeliai",
+      "summaryNoSize_few": "{{count}} modeliai",
+      "summaryNoSize_other": "{{count}} modelių",
       "summaryFailed": "Nepavyko apskaičiuoti atsisiuntimo dydžio. Bandykite dar kartą.",
       "empty": "Nerasta modelių failų atsisiuntimui.",
       "downloading": "Atsisiunčiama…",

frontend/src/pages/ProfilePage/activity/Heatmap.tsx

@@ -32,7 +32,7 @@ type Props = {
 /** GitHub's contribution graph: a column per week, a square per day, darker the busier the day. */
 export default function Heatmap({ range, days, selectedDay, today, onSelectDay }: Props) {
   const { t, i18n } = useTranslation("app");
-  // Monday-first in Lithuanian, as its calendars are; Sunday-first otherwise, as GitHub's is.
+  // Follows the locale's calendar: Sunday-first where it starts the week then (as GitHub does), Monday otherwise.
   const weekStart = weekStartFor(i18n.language);
   const weeks = React.useMemo(() => buildWeeks(range, weekStart), [range, weekStart]);
   const months = React.useMemo(() => monthStarts(weeks), [weeks]);

web/src/lib/site.mjs

@@ -291,7 +291,7 @@ export const DOCS = [
     group: "Features",
     title: "Themes and languages",
     nav: "Themes and languages",
-    description: "Light, dark or system theme, in English or Lithuanian.",
+    description: "Light, dark or system theme, in any language Thingport is translated into.",
   },
   {
     slug: "guides/system-health",