This pull request updates the language server's completion trigger behavior to improve the developer experience. The main change is the expansion of the set of characters that will trigger code completion suggestions.

Enhancements to code completion triggers:

• Expanded the trigger_characters in the language server's CompletionOptions to include "(" and "," in addition to ", so that code completion is now triggered when the user types a quote, parenthesis, or comma.
• Don't suggest the fixture name which is currently edited.
• Special handle the "," and add a space as prefix on insertion.