Preserve line terminator type when using --crlf and -r

[IsaacOscar]

This fixes a minor issue where the --crlf in combination with -r / --replace option causes matched lines to have there line terminators changed to \r\n, consider for example the following Fish shell line:

# printf 'hello\nworld\r\n' | rg --crlf '.' -r '$0' | string escape

Without this pull request, it prints:

hello\r
world\r

(So hello has magically had an \r added after to it)

With my pull request, the above prints:

hello
world\r

With this change, -r '$0' is now a no-op, i.e. rgs behaviour is now the same as if it was omitted.

(Note that a \r\n will still be inserted when the file does not end in a newline of any sort:

# printf 'hello\nworld' | rg --crlf '.' -r '$0' | string escape
hello
world\r

see issue #3097.)