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/mobile_vr/doc_classes/MobileVRInterface.xml

@@ -6,7 +6,7 @@
 	<description>
 		This is a generic mobile VR implementation where you need to provide details about the phone and HMD used. It does not rely on any existing framework. This is the most basic interface we have. For the best effect, you need a mobile phone with a gyroscope and accelerometer.
 		Note that even though there is no positional tracking, the camera will assume the headset is at a height of 1.85 meters. You can change this by setting [member eye_height].
-		You can initialise this interface as follows:
+		You can initialize this interface as follows:
 		[codeblock]
 		var interface = XRServer.find_interface("Native mobile")
 		if interface and interface.initialize():