[MM-33112] Add support for multiple custom spellchecking languages (#1743)

* [MM-33112] Add support for multiple custom spellchecking languages

* Styles and other formatting

* Type and lint fixes

* Update wording

src/common/config/defaultPreferences.ts

@@ -31,7 +31,7 @@ const defaultPreferences: ConfigV3 = {
     useSpellChecker: true,
     enableHardwareAcceleration: true,
     autostart: true,
-    spellCheckerLocale: 'en-US',
+    spellCheckerLocales: [],
     darkMode: false,
     downloadLocation: getDefaultDownloadLocation(),
 };

src/common/config/index.ts

@@ -235,8 +235,8 @@ export default class Config extends EventEmitter {
         return this.combinedData?.spellCheckerURL;
     }
 
-    get spellCheckerLocale() {
-        return this.combinedData?.spellCheckerLocale ?? defaultPreferences.spellCheckerLocale;
+    get spellCheckerLocales() {
+        return this.combinedData?.spellCheckerLocales ?? defaultPreferences.spellCheckerLocales;
     }
     get showTrayIcon() {
         return this.combinedData?.showTrayIcon ?? defaultPreferences.showTrayIcon;

src/common/config/upgradePreferences.ts

@@ -43,6 +43,7 @@ function upgradeV2toV3(configV2: ConfigV2) {
         };
     });
     config.lastActiveTeam = 0;
+    config.spellCheckerLocales = [];
     return config;
 }