Fix gcsm alias passing the commit message as a path

`gcsm` expanded to `git commit --all --signoff $message`, which hands
the message to git as a pathspec, so it fails with "pathspec did not
match" (or commits unrelated files if a file happens to share the
name). It should mirror `gcasm` minus the `--all`, as in oh-my-zsh:

    alias gcsm='git commit --signoff --message'

Also add `gcsm` to the abbreviation file, which mirrored every other
alias in this file except this one.

Author: DavSanchez

abbreviations/git/git-abbreviations.nu

@@ -58,6 +58,7 @@ const git_abbreviations = {
     gcav!: "git commit --all --verbose --no-verify --amend"
     gcfx: "git commit --fixup"
     gcv: "git commit --verbose --no-verify"
+    gcsm: "git commit --signoff --message"
     gcb: "git checkout -b"
     gcd: "git checkout develop"
     gcf: "git config --list"

aliases/git/git-aliases.nu

@@ -56,7 +56,7 @@ export def gcam [message: string] {
     git commit --all --message $message
 }
 export def gcsm [message: string] {
-    git commit --all --signoff $message
+    git commit --signoff --message $message
 }
 export alias gcas = git commit --all --signoff
 export def gcasm [message: string] {