CompletionItem.GetCompletionItemPriority improvement

[kindermannhubert]

Could be further improved by using Levenshtein distance instead of length comparison (=Math.Abs(...)expressions).

[kindermannhubert]

Implementation should be case sensitive and change of casing should have some non-zero penalty but lower than changing to an entirely different letter.

That would solve an issue when the completion list contains e.g. enum and Enum and the user writes Enum but enum is selected. Current matching is case insensitive.