Minor bug with help.autocorrect.

If you mis-type a git command starting with a non-letter, git internals will spit out some errors at you.

$ git 5fetch error: invalid key: pager.5fetch error: invalid key: alias.5fetch git: '5fetch' is not a git command. See 'git --help'.

Did you mean this?
        fetch

$ git \#fetch error: invalid key: pager.#fetch error: invalid key: alias.#fetch git: '#fetch' is not a git command. See 'git --help'.

Did you mean this?
        fetch