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`.

editor/editor_settings.cpp

@@ -159,7 +159,7 @@ bool EditorSettings::_get(const StringName &p_name, Variant &r_ret) const {
 
 			if (!sc->has_meta("original")) {
 				// Getting the meta when it doesn't exist will return an empty array. If the 'shortcut_events' have been cleared,
-				// we still want save the shortcut in this case so that shortcuts that the user has customised are not reset,
+				// we still want save the shortcut in this case so that shortcuts that the user has customized are not reset,
 				// even if the 'original' has not been populated yet. This can happen when calling save() from the Project Manager.
 				save_array.push_back(dict);
 				continue;