git format-patch --range-diff accepts non-quoted arguments (shouldn't it be?)

Hi,

I think it is rather odd that `git format-patch --range-diff` accepts <previous> argument without enclosed in quotes, since it is always multi-word (separated by space). E.g., below works:

     $ git format-patch <options> --range-diff=main..previous main..HEAD

but below returns nothing:

     $ git format-patch <options> --range-diff="main..previous main..HEAD"

Should the quoted <previous> argument to --range-diff be allowed, and forbid the unquoted counterpart?