[llvm-advisor] Fix RST documentation syntax error

Remove orphaned code block marker at end of file

- Fix 'Inline literal start-string without end-string' error
-m "- Update SEE ALSO section to follow LLVM CommandGuide standards"

Author: miguelcsx

llvm/docs/CommandGuide/llvm-advisor.rst

@@ -309,6 +309,4 @@ exit status.
 SEE ALSO
 --------
 
-:doc:`clang <clang>`, :doc:`opt`, :doc:`llc`
-
-```
+:manpage:`clang(1)`, :manpage:`opt(1)`, :manpage:`llc(1)`