[docs] design shuffle (#2951)

This PR incorporates design tweaks from #2922 without the home page or
content changes.

These are:
- Replacing all `hello@tldraw.com` with `sales@tldraw.com`
- Fix mailto links.
- Showing the first item in a section on direct routes to the section
- Splitting the article page for human-written content from article page
for generated content
- Splitting the layout for the landing page from the rest of the site
(temporarily identical to the regular content)
- Removing headings from left sidebar
- Restoring headings in right sidebar for human-written pages with > 1
heading link
- Styling block quote
- Adjusting section link appearance / layout in header / menu
- Changing the order of search results to preference docs over examples
- Updating copy on events
- Removing copy on user interface menus
- Adding hero as prop to all articles
- Updated icon
- Fixing a few broken links
- Replaces the sandpack code blocks with hljs code blocks, except in
examples.

### Change Type

- [x] `documentation` — Changes to the documentation only[^2]

apps/docs/scripts/functions/generateExamplesContent.ts

@@ -8,13 +8,14 @@ const section: InputSection = {
 	title: 'Examples',
 	description: 'Code recipes for bending tldraw to your will.',
 	categories: [
-		{ id: 'basic', title: 'Getting Started', description: '', groups: [] },
-		{ id: 'ui', title: 'UI & Theming', description: '', groups: [] },
-		{ id: 'shapes/tools', title: 'Shapes & Tools', description: '', groups: [] },
-		{ id: 'data/assets', title: 'Data & Assets', description: '', groups: [] },
-		{ id: 'editor-api', title: 'Editor API', description: '', groups: [] },
-		{ id: 'collaboration', title: 'Collaboration', description: '', groups: [] },
+		{ id: 'basic', title: 'Getting Started', description: '', groups: [], hero: null },
+		{ id: 'ui', title: 'UI & Theming', description: '', groups: [], hero: null },
+		{ id: 'shapes/tools', title: 'Shapes & Tools', description: '', groups: [], hero: null },
+		{ id: 'data/assets', title: 'Data & Assets', description: '', groups: [], hero: null },
+		{ id: 'editor-api', title: 'Editor API', description: '', groups: [], hero: null },
+		{ id: 'collaboration', title: 'Collaboration', description: '', groups: [], hero: null },
 	],
+	hero: null,
 	sidebar_behavior: 'show-links',
 }