patch 8.2.3584: "verbose set efm" reports location of the :compiler command

Problem:    "verbose set efm" reports the location of the :compiler command.
            (Gary Johnson)
Solution:   Add the "-keepscript" argument to :command and use it when
            defining CompilerSet.
diff --git a/runtime/doc/map.txt b/runtime/doc/map.txt
index 2c77355..f50377b 100644
--- a/runtime/doc/map.txt
+++ b/runtime/doc/map.txt
@@ -1569,6 +1569,9 @@
 	-register   The first argument to the command can be an optional
 		    register name (like :del, :put, :yank).
 	-buffer	    The command will only be available in the current buffer.
+	-keepscript Do not use the location of where the user command was
+		    defined for verbose messages, use the location of where
+		    the user command was invoked.
 
 In the cases of the -count and -register attributes, if the optional argument
 is supplied, it is removed from the argument list and is available to the