patch 9.1.1865: tests: do not notice lines containing only a tab

Problem:  tests: test_codestyle does not notice lines containing only a
          tab
Solution: Fix the whitespace issue in eval.txt, update test_codestyle to
          notice such issues (Hirohito Higashi)

closes: #18595

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/eval.txt

@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 9.1.  Last change: 2025 Oct 16
+*eval.txt*	For Vim version 9.1.  Last change: 2025 Oct 18
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar

src/testdir/test_codestyle.vim

@@ -137,7 +137,7 @@ def Test_help_files()
     # Check for unnecessary whitespace at the end of a line
     cursor(1, 1)
     while 1
-      lnum = search('[^/~\\]\s$')
+      lnum = search('\%([^/~\\]\|^\)\s\+$')
       # skip line that are known to have trailing white space
       if fname == 'map.txt' && getline(lnum) =~ "unmap @@ $"
         || fname == 'usr_12.txt' && getline(lnum) =~ "^\t/ \t$"

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1865,
 /**/
     1864,
 /**/