patch 9.1.0178: E1513 might be confusing

Problem:  E1513 might be confusing
          (Christoph Thoma)
Solution: reword error message, fix test to not
          depend on the actual message

fixes: #14189

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_winfixbuf.vim b/src/testdir/test_winfixbuf.vim
index 7f692f8..04043f8 100644
--- a/src/testdir/test_winfixbuf.vim
+++ b/src/testdir/test_winfixbuf.vim
@@ -493,7 +493,7 @@
   try
     browse edit! other
     call assert_equal(l:other, bufnr())
-  catch /E338:/
+  catch /^Vim\%((\a\+)\)\=:E338:/
     " Ignore E338, which occurs if console Vim is built with +browse.
     " Console Vim without +browse will treat this as a regular :edit.
   endtry
@@ -511,7 +511,7 @@
 
   try
     browse write other
-  catch /E338:/
+  catch /^Vim\%((\a\+)\)\=:E338:/
     " Ignore E338, which occurs if console Vim is built with +browse.
     " Console Vim without +browse will treat this as a regular :write.
   endtry
@@ -2532,7 +2532,7 @@
 
   try
     pyxdo test_winfixbuf_Test_pythonx_pyxdo_set_buffer()
-  catch /Vim(pyxdo):vim.error: Vim:E1513: Cannot edit buffer. 'winfixbuf' is enabled/
+  catch /Vim\%((\a\+)\)\=:E1513:/
     let l:caught = 1
   endtry
 
@@ -2563,7 +2563,7 @@
 
   try
     pyxfile file.py
-  catch /Vim(pyxfile):vim.error: Vim:E1513: Cannot edit buffer. 'winfixbuf' is enabled/
+  catch /Vim\%((\a\+)\)\=:E1513:/
     let l:caught = 1
   endtry
 
@@ -2596,7 +2596,7 @@
 buffer = vim.vars["_previous_buffer"]
 vim.current.buffer = vim.buffers[buffer]
 EOF
-  catch /Vim(pythonx):vim\.error: Vim:E1513: Cannot edit buffer. 'winfixbuf' is enabled/
+  catch /Vim\%((\a\+)\)\=:E1513:/
     let l:caught = 1
   endtry