feat: Adapt fish completion unit test for command with space

* Those test should currently fail
* We should escape quotes within command with space to prevent
  ❯ complete -c poetry -A -n '__fish_seen_subcommand_from 'env remove'' -l all -d 'Remove all managed virtual environments associated with the project.'
    complete: too many arguments

Author: riton

tests/commands/completion/fixtures/fish.txt

@@ -37,4 +37,4 @@ complete -c script -A -n '__fish_seen_subcommand_from hello' -l option-without-d
 # list
 
 # 'spaced command'
-complete -c script -A -n '__fish_seen_subcommand_from 'spaced command'' -l goodbye -d ''
+complete -c script -A -n '__fish_seen_subcommand_from \'spaced command\'' -l goodbye -d ''