feat: Translate frontend/src/i18n/en.json in bg

70% of minimum 50% translated source file: 'frontend/src/i18n/en.json'
on 'bg'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

frontend/src/i18n/bg.json

@@ -187,8 +187,8 @@
     "customStylesheet": "Потребителски Стилове",
     "defaultUserDescription": "Настройки по подразбиране за нови потребители.",
     "disableExternalLinks": "Забрани външните връзки (с изключение на документацията)",
-    "disableUsedDiskPercentage": "Disable used disk percentage graph",
-    "documentation": "documentation",
+    "disableUsedDiskPercentage": "Забрани графиката за използване на диска",
+    "documentation": "документация",
     "examples": "Examples",
     "executeOnShell": "Execute on shell",
     "executeOnShellDescription": "By default, File Browser executes the commands by calling their binaries directly. If you wish to run them on a shell instead (such as Bash or PowerShell), you can define it here with the required arguments and flags. If set, the command you execute will be appended as an argument. This applies to both user commands and event hooks.",