code: function _shortTitleForDocument(doc) {
          var fullPath = doc.file.fullPath;
  
          // If the document is untitled then return the filename, ("Untitled-n.ext");
          // otherwise show the project-relative path if the file is inside the
          // current project or the full absolute path if it's not in the project.
          if (doc.isUntitled()) {
              return fullPath.substring(fullPath.lastIndexOf("/") + 1);
          } else {
              return ProjectManager.makeProjectRelativeIfPossible(fullPath);
          }
      }
docs: Returns a short title for a given document.
  
  @param {Document} doc - the document to compute the short title for
  @return {string} - a short title for doc.