Add the two rehome commands in a bash alias file and comment them in the readme

Author: Skenvy

.bash_aliases

@@ -0,0 +1,19 @@
+source-existing-file ~/.include/.post/.bash_aliases
+
+################################################################################
+# Aliases used to proctor updating this repo when it's added as a submodule..
+# https://github.com/Skenvy/dotfiles?tab=readme-ov-file#use-as-home-is-another-repo
+# You'll need to manually run the dotfiles-submodule-symlinks the first time to
+# put the links in place (e.g. link _this_ file in place). But once you've done
+# that you can just "rehome" to update the submodule to latest.
+
+# For using this repo as a submodule
+alias rehome="git submodule update --remote && git add dotfiles && CLOBBER_HOME=GRACEFULLY ~/dotfiles/bin/dotfiles-submodule-symlinks && git diff --cached dotfiles && git status"
+alias rehome_undo="git restore --staged dotfiles && git restore dotfiles && git submodule update && CLOBBER_HOME=GRACEFULLY ~/dotfiles/bin/dotfiles-submodule-symlinks && git status"
+
+################################################################################
+# The above are two aliases relevant to using this repoistory as a submodule as
+# described by the README. For any additional aliases I use, I've added them
+# only in https://github.com/Skenvy/dotfiles/blob/home/.bash_aliases my home.
+
+source-existing-file ~/.include/.post/.bash_aliases

README.md

@@ -174,6 +174,9 @@ Now with a `.gitmodules` file that places **this repository** in the `dotfiles`
 ```
 With the submodule initialised and updated we can now symlink its contents into `$HOME`.
 
+> [!TIP]
+> Once you've followed the rest of these steps the _first_ time, repeating them again is as simple as using the `rehome` alias seen in [`main`'s `~/.bash_aliases`](https://github.com/Skenvy/dotfiles/blob/main/.bash_aliases).
+
 Remember to read the above section on [dotfiles-submodule-symlinks](https://github.com/Skenvy/dotfiles/tree/main?tab=readme-ov-file#dotfiles-submodule-symlinks) to understand how to manage the case of checking-in a file to the repository that submodules this one where the file matches a file path that already exists in this repository without having to set `CLOBBER_CHECKEDIN_ROOT` to its most destructive option of `REPLACE`.
 > [!CAUTION]
 > `CLOBBER_HOME=DESTRUCTIVELY` will **force** symlinks (`ln -sf`) to write over files.