Fix Bash learning link

[hussainanjar]

Learn → Bash currently opens devhints.io/bash, which fails to load. Point the menu entry to the same Bash cheatsheet in its author's GitHub repository.

Fixes #11183.

Validation:

• Reproduced the old link's connection error in the desktop browser and verified the replacement opens through the menu action. The replacement also returns HTTP 200.
• Menu and menu-guard tests, CLI suite, and git diff --check passed.
• Ran ./test/all: 230 of 236 shell test files passed. All six failures reproduce on unchanged upstream: bar icon geometry, About animation, three checks requiring the absent omarchy-pkgs checkout, and the locate test reading bytecode generated by an earlier collector test as UTF-8.