runtime(misc): Use consistent "Vim script" spelling

References: https://groups.google.com/g/vim_dev/c/3Z5yM8KER2w/m/wAqws0QSEAAJ

closes: #15863

Signed-off-by: h-east <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index 6acfe00..5dedce5 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -929,7 +929,7 @@
     #" String conversion.
     call assert_equal('hello from ' .. v:version, $"hello from {v:version}")
     call assert_equal('hello from ' .. v:version, $'hello from {v:version}')
-    #" Paper over a small difference between VimScript behaviour.
+    #" Paper over a small difference between Vim script behaviour.
     call assert_equal(string(v:true), $"{v:true}")
     call assert_equal('(1+1=2)', $"(1+1={1 + 1})")
     #" Hex-escaped opening brace: char2nr('{') == 0x7b