Add a mdx override for the edit on github link

docs/config/keybind/reference.mdx

@@ -1,6 +1,7 @@
 ---
 title: Keybinding Action Reference
 description: Reference of all Ghostty keybinding actions.
+editOnGithubLink: https://github.com/ghostty-org/ghostty/edit/main/src/input/Binding.zig
 ---
 
 This is a reference of all Ghostty keybinding actions.

docs/config/reference.mdx

@@ -1,6 +1,7 @@
 ---
 title: Reference
 description: Reference of all Ghostty configuration options.
+editOnGithubLink: https://github.com/ghostty-org/ghostty/edit/main/src/config/Config.zig
 ---
 
 This is a reference of all Ghostty configuration options. These
@@ -2061,4 +2062,3 @@ Changing this configuration requires a full restart of
 Ghostty to take effect.
 
 This only works on macOS since only macOS has an auto-update feature.
-

src/lib/fetch-docs.ts

@@ -29,6 +29,11 @@ export interface DocsPageData {
   slug: string;
   title: string;
   description: string;
+  // There are scenarios in which the GitHub link should
+  // not be the website source MDX file, due to the MDX being
+  // generated from some upstream source. This is an optional
+  // frontmatter that can override the link.
+  editOnGithubLink: string | null;
   hideSidecar: boolean;
   content: MDXRemoteSerializeResult;
   relativeFilePath: string;
@@ -94,6 +99,9 @@ async function loadDocsPageFromRelativeFilePath(
     relativeFilePath,
     title: mdxFileContent.data.title,
     description: mdxFileContent.data.description,
+    editOnGithubLink: mdxFileContent.data.editOnGithubLink
+      ? mdxFileContent.data.editOnGithubLink
+      : null,
     hideSidecar: mdxFileContent.data.hasOwnProperty("hideSidecar")
       ? mdxFileContent.data.hideSidecar
       : false,

src/pages/docs/[...path]/index.tsx

@@ -72,13 +72,20 @@ export default function DocsPage({
   docsPageData: {
     title,
     description,
+    editOnGithubLink,
     content,
     relativeFilePath,
     pageHeaders,
     hideSidecar,
   },
   breadcrumbs,
 }: DocsPageProps) {
+  // Calculate the "Edit in Github" link. If it's not provided
+  // in the frontmatter, point to the website repo mdx file.
+  editOnGithubLink = editOnGithubLink
+    ? editOnGithubLink
+    : `${GITHUB_REPO_URL}/edit/main/${relativeFilePath}`;
+
   return (
     <NavFooterLayout
       docsNavTree={navTreeData}
@@ -126,7 +133,7 @@ export default function DocsPage({
             <CustomMDX content={content} />
             <br />
             <div className={s.editOnGithub}>
-              <a href={`${GITHUB_REPO_URL}/edit/main/${relativeFilePath}`}>
+              <a href={editOnGithubLink}>
                 Edit on GitHub <Pencil size={14} />
               </a>
             </div>