This PR adds two more cases to existing LSP completion cases.

- When text_edit exists:  (New test)
   1. we use text_edit, over insert_text and label

- When edit range exists (and text_edit is None):  (New test)
   1. insert_text is used over label if exists
   2. label is used otherwise

- When not edit range exists (and text_edit is None):  (Existing test)
   1. insert_text is used over label if exists
   2. label is used otherwise

Release Notes:

- N/A