fixed typo in scope_method.cson

fixes typo in  scope_method.cson

Error reading snippets file '/Users/username/.atom/packages/angularjs-snippets/snippets/scope_method.cson': [stdin]:1:15: error: unexpected :
``'.source.js':
              ^ /Applications/Atom.app/Contents/Resources/app/node_modules/snippets/lib/snippets.js:132