runtime(doc): minor updates.

closes: #15280

Signed-off-by: Shane Harper <shane@shaneharper.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index eddafd0..b921cb5 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 9.1.  Last change: 2024 Jun 01
+*eval.txt*	For Vim version 9.1.  Last change: 2024 Jul 17
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -3124,9 +3124,10 @@
 				let lconst[0] = 2  " Error!
 				let lconst[1][0] = 'b'  " OK
 <							*E995*
-			|:const| does not allow to for changing a variable: >
+			It is an error to specify an existing variable with
+			:const. >
 				:let x = 1
-				:const x = 2  " Error!
+				:const x = 1  " Error!
 <							*E996*
 			Note that environment variables, option values and
 			register values cannot be used here, since they cannot