patch 9.1.1214: matchfuzzy() can be improved for camel case matches

patch 9.1.1214: matchfuzzy() can be improved for camel case matches

Problem:  When searching for "Cur", CamelCase matches like "lCursor" score
          higher than exact prefix matches like Cursor, which is
          counter-intuitive (Maxim Kim).
Solution: Add a 'camelcase' option to matchfuzzy() that lets users disable
          CamelCase bonuses when needed, making prefix matches rank higher.
          (glepnir)

fixes: #16504
closes: #16797

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