patch 9.1.0765: No test for patches 6.2.418 and 7.3.489

Problem:  No test for patches 6.2.418 and 7.3.489
Solution: Add a test.  Fix some whitespace problems in test_mapping.vim.
          Document the behavior (zeertzjq).

closes: #15815

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/map.txt b/runtime/doc/map.txt
index ec94435..2773140 100644
--- a/runtime/doc/map.txt
+++ b/runtime/doc/map.txt
@@ -1,4 +1,4 @@
-*map.txt*       For Vim version 9.1.  Last change: 2024 Sep 26
+*map.txt*       For Vim version 9.1.  Last change: 2024 Oct 07
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -84,6 +84,8 @@
 			where the map command applies.  Disallow mapping of
 			{rhs}, to avoid nested and recursive mappings.  Often
 			used to redefine a command.
+			Note: Keys in {rhs} also won't trigger abbreviation,
+			with the exception of |i_CTRL-]| and |c_CTRL-]|.
 			Note: When <Plug> appears in the {rhs} this part is
 			always applied even if remapping is disallowed.