feat(git): add function for updating git submodules (#33)

Reviewed-on: https://codeberg.org/vlw/dotfiles/pulls/33

.bash_aliases

@@ -95,6 +95,12 @@ gitf () {
             git pull "$remote" $(git rev-parse --abbrev-ref HEAD)
             ;;
 
+        # Update all git submodules in this repo. "sd" for submodule download.
+        "sd")
+            # Only supports "master" as branch for now. This could cause unexpected results if a tracked submodule has a different branch or location name
+            git submodule foreach "(git checkout master; git pull)"
+            ;;
+
         # Push commited changes (current branch) to a remote (defaults to "origin"). "u" for upload.
         "u")
             local remote="${2:-origin}"