patch 9.0.1403: unused variables and functions

Problem:    Unused variables and functions.
Solution:   Delete items and adjust #ifdefs. (Dominique Pellé, closes #12145)
diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index da2bf32..0bdeabf 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -2994,7 +2994,7 @@
 		Can also be used as a |method|: >
 			GetFuncname()->funcref([arg])
 <
-				*function()* *partial* *E700* *E922* *E923*
+				*function()* *partial* *E700* *E923*
 function({name} [, {arglist}] [, {dict}])
 		Return a |Funcref| variable that refers to function {name}.
 		{name} can be the name of a user defined function or an