i18n: Configure i18-next to remove unused strings

This is to make it easier to rename keys.

Author: claremacrae

.gitignore

@@ -49,5 +49,8 @@ yarn-error.log
 # Backup files.
 *.bak
 
+# Internationalisation
+/src/i18n/locales/*_old.json
+
 # VS code config
 .vscode/

i18next-parser.config.js

@@ -19,7 +19,7 @@ module.exports = {
     useKeysAsDefaultValue: true, // Use keys for default values if no translation exists
     resetDefaultValueLocale: null, // Retain existing default values
     sort: true, // Sort keys alphabetically
-    keepRemoved: true, // Keep keys not found in source files
+    keepRemoved: false, // Keep keys not found in source files. Removed values are written to *_old.json files
     jsonIndent: 2, // Pretty-print JSON
     lexers: {
         ts: ['JavascriptLexer'], // TypeScript files