Prevents sed from returning an error for arguments containing filenames:
$ git sed src/foo.c src/bar.c
sed: -e expression #1, char 13: unknown option to `s'
Prevents running sed when the search pattern does not match any files.
This results in sed printing an unnessecary warning:
$ git sed foo bar
sed: no input files
Otherwise filenames with spaces result in errors:
$ cat "file with spaces in name"
old
$ git sed old new
sed: can't read file: No such file or directory
sed: can't read with: No such file or directory
sed: can't read spaces: No such file or directory
sed: can't read in: No such file or directory
sed: can't read name: No such file or directory
