vim-patch:ddbb6fe: runtime(vim): Update base-syntax, improve :set highlighting (#29850)

- Match bang, "all" and "termcap" options, and trailing command
  separator "|".
- Highlight set assignment operators.
- Match multiline :set and multiline option values.
- Mention the newer "0o" octal prefix at :help :set=.

closes: vim/vim#15329

ddbb6fe2d0

Co-authored-by: Doug Kearns <dougkearns@gmail.com>

runtime/doc/options.txt

@@ -58,7 +58,8 @@ achieve special effects.  These options come in three forms:
 :se[t] {option}:{value}
 			Set string or number option to {value}.
 			For numeric options the value can be given in decimal,
-			hex (preceded with 0x) or octal (preceded with '0').
+			hex (preceded with 0x) or octal (preceded with '0' or
+			'0o').
 			The old value can be inserted by typing 'wildchar' (by
 			default this is a <Tab>).  Many string options with
 			fixed syntax also support completing known values.