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`.

doc/classes/EditorCommandPalette.xml

@@ -5,7 +5,7 @@
 	</brief_description>
 	<description>
 		Object that holds all the available Commands and their shortcuts text. These Commands can be accessed through [b]Editor &gt; Command Palette[/b] menu.
-		Command key names use slash delimiters to distinguish sections Example: [code]"example/command1"[/code] then [code]example[/code] will be the section name.
+		Command key names use slash delimiters to distinguish sections, for example: [code]"example/command1"[/code] then [code]example[/code] will be the section name.
 		[codeblocks]
 		[gdscript]
 		var command_palette = get_editor_interface().get_command_palette()