Add Completion To GIT Version Of DMS.

## Feature Description

When Install DMS From GIT Version completion.bash is not installed

## Use Case

Streamlined With Stable Build Also Users Using GIT Version Won't Miss-out On Such A Good Feature.

## Compositor

Is this feature specific to one compositor?

- [x] All compositors
- [ ] niri
- [ ] Hyprland
- [ ] dwl (MangoWC)
- [ ] sway

## Proposed Solution

Same As Stable Verizon. (Auto Install For Existing Users With Update)

## Alternatives/Existing Solutions

Same As Stable Verizon.

Start by comparing the stable-build and GIT-version installation or update paths, then locate where completion.bash is installed. Confirm how existing users receive updates. Done means a GIT-version install and update install completion.bash consistently with the stable version.

Written by the indexing model from the issue text.