Style: Misc docs and comment style and language fixes

- Removed empty paragraphs in XML.
- Consistently use bold style for "Example:", on a new line.
- Fix usage of `[code]` when hyperlinks could be used (`[member]`, `[constant]`).
- Fix invalid usage of backticks for inline code in BBCode.
- Fix some American/British English spelling inconsistencies.
- Other minor fixes spotted along the way, including typo fixes with codespell.
- Don't specify `@GlobalScope` for `enum` and `constant`.

modules/multiplayer/scene_replication_interface.cpp

@@ -325,7 +325,7 @@ Error SceneReplicationInterface::_update_spawn_visibility(int p_peer, const Obje
 		// Check visibility for each peers.
 		for (const KeyValue<int, PeerInfo> &E : peers_info) {
 			if (is_visible) {
-				// This is fast, since the the object is visibile to everyone, we don't need to check each peer.
+				// This is fast, since the the object is visible to everyone, we don't need to check each peer.
 				if (E.value.spawn_nodes.has(p_oid)) {
 					// Already spawned.
 					continue;