[codex] Document GNOME Wayland shortcut workaround

[jhihweijhan]

Summary

• Document a persistent wrapper-script workaround for GNOME Wayland custom shortcuts.
• Show how to bind the wrapper to Ctrl+Print while keeping the default GNOME screenshot UI on Print.
• Explain why the shortcut command should use an absolute path.

Why

GNOME Wayland users can hit Unable to capture screen when launching flameshot gui from a desktop shortcut even when the same command works from a terminal.
The page already documents shell-based workarounds; this adds a persistent custom-shortcut example for users who want the setting to survive reboot.

Related issues: flameshot-org/flameshot#3365, flameshot-org/flameshot#3326.

Validation

• zola build completed successfully with Zola 0.22.1.
• Existing Bootstrap contrast warning still appears; no new build errors.
• Checked rendered DOM for /docs/guide/wayland-help/ and confirmed the new flameshot-gui-wayland / Ctrl + Print content is present.
• Checked docs navigation pages: /docs/, /docs/installation/installation-linux/, and /docs/guide/key-bindings/.
• Confirmed search_index.en.js includes the new Wayland shortcut content.
• Captured desktop and mobile Chrome headless screenshots for the Wayland help page.

[mmahmoudian]

I believe this is unnecessary because same information is already in that page:

https://flameshot.org/docs/guide/wayland-help/#gnome-shortcut-does-not-trigger-flameshot

But if you want, you can add the information about ~ expansion to the (line 90 of your diff) and lines 85 and 86 to "Gnome shortcut does not trigger Flameshot" section. I believe this would be helpful for others.