message: docs: fix closing of code block in merge documentation
  remove hanging 'javascript' after ``` which breaks formatting of documentation
  Closes
diff: @@ -48,7 +48,7 @@ export function merge<T, R>(...observables: (ObservableInput<any> | SchedulerLik
  * // clicks logs MouseEvents to console everytime the "document" is clicked
  * // Since the two streams are merged you see these happening
  * // as they occur.
  - * ```javascript
  + * ```
  *
  * ### Merge together 3 Observables, but only 2 run concurrently
  * ```javascript
  