appendTabstop 
  Builder-function that appends a tabstop ($1, $2 etc) to the {@linkcode SnippetString.value value} of this snippet string.
Parameters
number
The number of this tabstop, defaults to an auto-increment value starting at 1.
Builder-function that appends a tabstop ($1, $2 etc) to the {@linkcode SnippetString.value value} of this snippet string.
The number of this tabstop, defaults to an auto-increment value starting at 1.