urls: Move /why-zulip pages to the corporate folder.

corporate/urls.py

@@ -68,7 +68,7 @@ landing_page_urls = [
     path("attribution/", landing_view, {"template_name": "corporate/attribution.html"}),
     path("team/", team_view),
     path("history/", landing_view, {"template_name": "corporate/history.html"}),
-    path("why-zulip/", landing_view, {"template_name": "zerver/why-zulip.html"}),
+    path("why-zulip/", landing_view, {"template_name": "corporate/why-zulip.html"}),
     path("self-hosting/", landing_view, {"template_name": "zerver/self-hosting.html"}),
     path("security/", landing_view, {"template_name": "zerver/security.html"}),
     # /for pages

templates/corporate/why-zulip.html

@@ -28,7 +28,7 @@
     <div class="main">
         <div class="padded-content">
             <div class="inner-content markdown">
-                {{ render_markdown_path('zerver/why-zulip.md') }}
+                {{ render_markdown_path('corporate/why-zulip.md') }}
             </div>
         </div>
     </div>