[site] Allow URLs of the form scenedetect.com/issue/200

Author: Breakthrough

website/mkdocs.yml

@@ -39,3 +39,6 @@ markdown_extensions: [fenced_code]
 
 extra_css:
   - style.css
+
+extra_javascript:
+  - redirect.js

website/pages/issue.md

@@ -0,0 +1,4 @@
+
+# Going to Github Issues...
+
+Redirecting to Github Issues.

website/pages/issues.md

@@ -0,0 +1,4 @@
+
+# Going to Github Issues...
+
+Redirecting to Github Issues.

website/pages/redirect.js

@@ -0,0 +1,22 @@
+
+(function() {
+    var path = window.location.pathname;
+
+    const TARGETS = [ 'issue', 'issues' ]
+    for (const target of TARGETS) {
+        if (path == target) {
+                window.location.href = 'https://github.com/Breakthrough/PySceneDetect/issues/';
+        }
+    }
+
+    const PREFIXES = ['/issue/', '/issues/']
+    for (const prefix of PREFIXES) {
+        if (path.startsWith(prefix)) {
+            var issueNumber = path.substring(prefix.length);
+            if (issueNumber) {
+                var newUrl = 'https://github.com/Breakthrough/PySceneDetect/issues/' + issueNumber;
+                window.location.href = newUrl;
+            }
+        }
+    }
+})();