docs: add contributing page

Author: 42willow

.vitepress/config.mts

@@ -25,6 +25,7 @@ export default defineConfig({
           { text: "Customisation", link: "/customisation" },
           { text: "Integrations", link: "/integrations" },
           { text: "Keyboard Shortcuts", link: "/shortcuts" },
+          { text: "Contributing", link: "/contributing" },
         ],
       },
     ],

src/contributing.md

@@ -0,0 +1,33 @@
+---
+outline: false
+---
+
+# Contributing
+
+If you want to get your change merged into the main project, please follow the [contribution guidelines](https://github.com/cascadefox/cascade/blob/main/contributing.md)
+
+## Inspecting the browser window
+
+To inspect Firefox's UI you can use the [Browser Toolbox](https://developer.mozilla.org/en-US/docs/Tools/Browser_Toolbox).
+
+### Enable the Browser Toolbox
+
+1. Press `F12` to open the Page Inspector.
+
+   **Alternate:** Right click the page then "Inspect Element (Q)".
+
+2. Press `F1` to open the Page Inspector Settings.
+
+   **Alternate:** In the top right of the Page Inspector next to the close button; press the "⋯" button then "Settings".
+
+3. Ensure the following settings are checked:
+   - "Enable browser chrome and add-on debugging toolbox"
+   - "Enable remote debugging"
+
+### Open the Browser Toolbox
+
+Press `alt`, "Tools", "Browser Tools" then "Browser Toolbox".
+
+**Alternate:** Press `ctrl` + `alt` + `shift` + `i`
+
+<sub>Instructions adapted from [user1189731](https://superuser.com/users/1189731/user1189731)'s [post](https://superuser.com/a/1608642)</sub>