"Mark as Plain Text" API?

private boolean markFileAsPlainText (VirtualFile file) {
          if (!file.exists() || file.isDirectory()) return false;

          EnforcedPlainTextFileTypeManager typeManager = EnforcedPlainTextFileTypeManager.getInstance();
          assert typeManager != null;
          if (EnforcedPlainTextFileTypeManager.isApplicableFor(file) &&
                    !typeManager.isMarkedAsPlainText(file)) {
               typeManager.markAsPlainText(file);
               return true;
          }

          return false;
     }

I have done something similar for all files
https://github.com/krasa/UsefulActions/blob/master/src/krasa/usefulactions/MarkFolderAsPlainText.java

I already have this functionality on my plugin too. https://github.com/Salerman/MarkDirFilesAsPlain :)