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/mobile_vr_interface.cpp

@@ -155,7 +155,7 @@ void MobileVRInterface::set_position_from_sensors() {
 	last_magnetometer_data = magneto;
 
 	if (grav.length() < 0.1) {
-		// not ideal but use our accelerometer, this will contain shaky user behaviour
+		// not ideal but use our accelerometer, this will contain shaky user behavior
 		// maybe look into some math but I'm guessing that if this isn't available, it's because we lack the gyro sensor to actually work out
 		// what a stable gravity vector is
 		grav = acc;