patch 8.2.3235: cannot use lambda in {} block in user command

Problem:    Cannot use lambda in {} block in user command. (Martin Tournoij)
Solution:   Do not go over the end of the lambda.

src/testdir/test_usercommands.vim

@@ -632,6 +632,13 @@ func Test_usercmd_with_block()
   call assert_equal('more', g:didmore)
   unlet g:didit
   unlet g:didmore
+  delcommand DoSomething
+
+  command DoMap {
+	echo [1, 2, 3]->map((_, v) => v + 1)
+    }
+  DoMap
+  delcommand DoMap
 
   let lines =<< trim END
       command DoesNotEnd {

src/userfunc.c

@@ -1398,7 +1398,7 @@ get_lambda_tv(
 
 	// If there are line breaks, we need to split up the string.
 	line_end = vim_strchr(start, '\n');
-	if (line_end == NULL)
+	if (line_end == NULL || line_end > end)
 	    line_end = end;
 
 	// Add "return " before the expression (or the first line).

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3235,
 /**/
     3234,
 /**/