Fix wording in doc comment

Author: AliSoftware

lib/fastlane/plugin/wpmreleasetoolkit/actions/ios/ios_merge_strings_files.rb

@@ -31,7 +31,7 @@ def self.details
           The action only supports merging files which are in the OpenStep (`"key" = "value";`) text format (which is
           the most common format for `.strings` files, and the one generated by `genstrings`), but can handle the case
           of different files using different encodings (UTF8 vs UTF16) and is able to detect and report duplicates.
-          It does not handle strings files in XML or binary-plist formats `.strings` files (which are valid but more rare)
+          It does not handle `.strings` files in XML or binary-plist formats (which are valid but more rare)
         DETAILS
       end