git: Use switch instead of checkout if available

For git versions that support it, the aliases will use the newer
`switch` instruction instead of `checkout` for its use cases.
Creating a new branch through `gcb` is for example done by
`git switch -c` instead of the older `git checkout -b`.

Additionally streamlined git version checking to be a little faster and
to unify its approach on posix sh, bash and zsh instead of utilizing
individual checking functions.

git/.config/bash/alias.d/git-stash-push.sh

@@ -1,9 +0,0 @@
-#!/usr/bin/env bash
-
-if ! exist git; then
-    return 1
-fi
-
-# while zsh can detect versions, bash
-# in shells other than zsh, simply fall back to save
-alias gsta='git stash save'

git/.config/sh/alias.d/git.sh

@@ -4,7 +4,9 @@ if ! exist git; then
     return 1
 fi
 
-# git alias
+# print git version output and get raw version number by stripping prefix
+git_version=$(git --version 2>/dev/null)
+git_version="${git_version##git version }"
 
 alias g='git'
 
@@ -18,10 +20,17 @@ alias gc='git commit -v'
 alias gc!='git commit -v --amend'
 alias gcn!='git commit -v --no-edit --amend'
 
-alias gcm='git checkout master 2>/dev/null || git checkout main'
-alias gcd='git checkout develop'
-alias gcb='git checkout -b'
-alias gco='git checkout'
+if version_at_least 2.23 "$git_version"; then
+    alias gcm='git switch master 2>/dev/null || git switch main'
+    alias gcd='git switch develop'
+    alias gcb='git switch -c'
+    alias gco='git switch'
+else
+    alias gcm='git checkout master 2>/dev/null || git checkout main'
+    alias gcd='git checkout develop'
+    alias gcb='git checkout -b'
+    alias gco='git checkout'
+fi
 
 alias gd='git diff'
 alias gds='git diff --staged'
@@ -59,7 +68,13 @@ alias grbm='git rebase master || git rebase main'
 
 alias gst='git status'
 
-# stash push/save is handled differently by zsh/bash
 alias gstp='git stash pop'
 alias gstl='git stash list'
 alias gstL='git stash list --stat'
+if version_at_least 2.13 "$git_version"; then
+    alias gsta='git stash push'
+else
+    alias gsta='git stash save'
+fi
+
+unset -v git_version

git/.config/zsh/alias.d/git-stash-push.sh

@@ -1,15 +0,0 @@
-#!/usr/bin/env zsh
-# shellcheck shell=sh
-
-if ! exist git; then
-    return 1
-fi
-
-# git alias
-# if git is at least version 2.13, we can use git stash push
-autoload -Uz is-at-least
-if is-at-least 2.13 "$(git --version 2>/dev/null | awk '{print $3}')"; then
-    alias gsta='git stash push'
-else
-    alias gsta='git stash save'
-fi