Refactor some internal methods in CompletionHandler to increase readability
Refactor some internal methods in CompletionHandler to increase readability

* Simplified formatArugments and combine it with completionForCommandArgs.
  The formatArguments method exists from the initial commit, but I can't
  work out what the name was intended to mean. Refactoring this method out
  removes the need to figure out a sensical name for it.
* Extracted option literals generation from mapArgumentsToWords to it's own
  method.
* Removed unnecessary class aliases

omero/symfony-console-completion,k0pernikus/symfony-console-completion,stecman/symfony-console-completion