Adding a message at end of linting each target

See @mokagio's suggestion in #18427 (comment)

Author: AliSoftware

Scripts/BuildPhases/LintAppLocalizedStringsUsage.rb

@@ -35,6 +35,7 @@ def lint(file_path:, target_name:)
   puts "Linting extension target #{target.name} for improper NSLocalizedString usage..."
   source_files = build_phase.files_references.map(&:real_path).select { |f| ['.m', '.swift'].any? { |ext| f.extname == ext } }
   source_files.each { |f| violations_count += lint(file_path: f, target_name: target.name) }
+  puts "Done."
 end
 
 exit 1 if violations_count > 0