Searches the end of a multi line comment or string.
endSearcher defines the pattern of the searched item.
end: OUT stores the end of the item.
Returns null on success or the error message.
Finds the end of a single line string constant.
end specifies the string end (" or ').
If hasPrefixR the string constant is a "raw string" that means meta chars
take not place there.
endPosition: OUT the position behind the end delimiter.
Returns null on success, otherwise the error message.