patch 9.1.1325: tests: not checking error numbers properly

Problem:  tests: not checking error numbers properly.
Solution: Add a trailing comma to avoid matching a different error
          number with the same prefix (zeertzjq)

closes: #17159

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_startup.vim b/src/testdir/test_startup.vim
index 0387674..bc437a9 100644
--- a/src/testdir/test_startup.vim
+++ b/src/testdir/test_startup.vim
@@ -1441,7 +1441,7 @@
   let logfile = 'Xcq_log.txt'
   let out = system(GetVimCommand() .. ' --clean --log ' .. logfile .. ' -es -X -c "argdelete foobar" -c"7cq"')
   call assert_equal(8, v:shell_error)
-  let log = filter(readfile(logfile), {idx, val -> val =~ "E480"})
+  let log = filter(readfile(logfile), {idx, val -> val =~ "E480:"})
   call assert_match('E480: No match: foobar', log[0])
   call delete(logfile)
 
@@ -1452,7 +1452,7 @@
   else
     call assert_equal(256, v:shell_error)
   endif
-  let log = filter(readfile(logfile), {idx, val -> val =~ "E480"})
+  let log = filter(readfile(logfile), {idx, val -> val =~ "E480:"})
   call assert_match('E480: No match: foobar', log[0])
   call delete('Xcq_log.txt')
 endfunc