Fish completions aren't showing the flags of the subcommands correctly

Environment info

• OS
  • Linux
  • Mac OS X
  • Windows
  • Others:
• Shell
  • bash
  • zsh
  • fish

Problem / Steps to reproduce

Full fish completions are relatively new, but some of them are behaving strangely.

Ideally, when you do something like

gbl --<TAB>

You get all the flags available to pass into git blame:

> git blame --help
--contents  (Instead of working tree, use the contents of the named file)  --line-porcelain                     (Show the porcelain format)  --show-email  (Show the author email instead of author name)
--date                        (Specifies the format used to output dates)  --porcelain  (Show in a format designed for machine consumption)  --show-name       (Show the filename in the original commit)
--help                                  (Display manual of a Git command)  --reverse             (Walk history forward instead of backward)  --show-number  (Show the line number in the original commit)
--incremental                             (Show the result incrementally)  --root                 (Do not treat root commits as boundaries)  --show-stats                 (Include additional statistics)

Instead you get:

> git-forgit blame --

Nothing.

It seems like we are completing the files correctly, but not wrapping the flags. Filing this for the future