Add rubocop-i18n linter (mastodon#34057)

Author: dmathieu

.rubocop.yml

@@ -18,6 +18,7 @@ inherit_from:
   - .rubocop/rspec_rails.yml
   - .rubocop/rspec.yml
   - .rubocop/style.yml
+  - .rubocop/i18n.yml
   - .rubocop/custom.yml
   - .rubocop_todo.yml
   - .rubocop/strict.yml
@@ -30,6 +31,7 @@ plugins:
   - rubocop-rails
   - rubocop-rspec
   - rubocop-performance
+  - rubocop-i18n
 
 require:
   - rubocop-rspec_rails

.rubocop/i18n.yml

@@ -0,0 +1,12 @@
+I18n/RailsI18n:
+  Enabled: true
+  Exclude:
+    - 'config/**/*'
+    - 'db/**/*'
+    - 'lib/**/*'
+    - 'spec/**/*'
+I18n/GetText:
+  Enabled: false
+
+I18n/RailsI18n/DecorateStringFormattingUsingInterpolation:
+  Enabled: false

Gemfile

@@ -165,6 +165,7 @@ group :development do
   # Code linting CLI and plugins
   gem 'rubocop', require: false
   gem 'rubocop-capybara', require: false
+  gem 'rubocop-i18n', require: false
   gem 'rubocop-performance', require: false
   gem 'rubocop-rails', require: false
   gem 'rubocop-rspec', require: false

Gemfile.lock

@@ -719,7 +719,7 @@ GEM
       rspec-mocks (~> 3.0)
       sidekiq (>= 5, < 8)
     rspec-support (3.13.2)
-    rubocop (1.73.1)
+    rubocop (1.73.2)
       json (~> 2.3)
       language_server-protocol (~> 3.17.0.2)
       lint_roller (~> 1.1.0)
@@ -734,6 +734,9 @@ GEM
       parser (>= 3.3.1.0)
     rubocop-capybara (2.21.0)
       rubocop (~> 1.41)
+    rubocop-i18n (3.2.3)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.72.1)
     rubocop-performance (1.24.0)
       lint_roller (~> 1.1)
       rubocop (>= 1.72.1, < 2.0)
@@ -1016,6 +1019,7 @@ DEPENDENCIES
   rspec-sidekiq (~> 5.0)
   rubocop
   rubocop-capybara
+  rubocop-i18n
   rubocop-performance
   rubocop-rails
   rubocop-rspec

app/lib/video_metadata_extractor.rb

@@ -12,7 +12,7 @@ def initialize(path)
   rescue Terrapin::ExitStatusError, Oj::ParseError
     @invalid = true
   rescue Terrapin::CommandNotFoundError
-    raise Paperclip::Errors::CommandNotFoundError, 'Could not run the `ffprobe` command. Please install ffmpeg.'
+    raise Paperclip::Errors::CommandNotFoundError, 'Could not run the `ffprobe` command. Please install ffmpeg.' # rubocop:disable I18n/RailsI18n/DecorateString -- This error is not user-facing
   end
 
   def valid?