replace old ruby :KEY => VALUE syntax with the new one KEY: VALUE with sublime find & replace

PLEASE DO IT CAREFULLY, SPECIAL CASES MAY OCCUR, SO BULK REPLACE IS NOT RECOMMENDED

find: (:)(((?!:).)*?)(\s*=>)
replace: ${2}:
  
explanation:
    i. the brackets are used to create capture/matches groups, so that you can ommit the : (group 1) and the => (group 3)
        and use only the key (group 2)
    ii. ((?!:).)*? finds KEY text, it searches any text, expect it should not have : included, that's the role of (?!:) part,
        the ? is used to mark a non-greedy search, if not marked, some text like :KEY1 => VAL1, :KEY2 => VAL2 will end up 
        as (:), (KEY1 => VAL1, :KEY2) and (=>) as the groups
    iii. the replacement ${2}: takes the second group and appends : to it
    
references:
    https://forum.sublimetext.com/t/search-with-regex-and-replace-with-found-text/26914/2
    https://stackoverflow.com/questions/2503413/regular-expression-to-stop-at-first-match
    https://www.regextester.com/15