Replace Riot with Element in docs and comments

This only covers the simple cases of references to issues and repos. More
complex areas, such as deployment scripts, will be handled separately.

Part of https://github.com/vector-im/element-web/issues/14864

src/components/structures/LoggedInView.tsx

@@ -596,7 +596,7 @@ class LoggedInView extends React.Component<IProps, IState> {
         const maxRadius = 5; // People shouldn't be straying too far, hopefully
 
         // Note: we track how far the user moved their mouse to help
-        // combat against https://github.com/vector-im/riot-web/issues/7158
+        // combat against https://github.com/vector-im/element-web/issues/7158
 
         if (distance < maxRadius) {
             // This is probably a real click, and not a drag