patch 9.1.1049: insert-completed items are always sorted

patch 9.1.1049: insert-completed items are always sorted

Problem:  insert-completed items are always sorted, although the LSP
          spec[1] standard defines sortText in the returned
          completionitem list. This means that the server has sorted the
          results. When fuzzy is enabled, this will break the server's
          sorting results.
Solution: disable sorting of candidates when "nosort" is set in
          'completeopt'

[1]
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#completionItem

closes: #16501

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>