runtime(vim): Update base-syntax, match shebang lines (#15011)

Match shebang lines in Vim9 and legacy script.

Mark these as an error if they appear anywhere other than the first line
of a legacy-script file.  In Vim9 script these match as normal line
comments rather than an error.

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/testdir/input/vim9_shebang.vim b/runtime/syntax/testdir/input/vim9_shebang.vim
new file mode 100755
index 0000000..c012fd9
--- /dev/null
+++ b/runtime/syntax/testdir/input/vim9_shebang.vim
@@ -0,0 +1,7 @@
+#!/usr/bin/env vim -S
+vim9script
+
+# Vim shebang line
+
+# just a line comment
+#!/usr/bin/env vim -S
diff --git a/runtime/syntax/testdir/input/vim_shebang.vim b/runtime/syntax/testdir/input/vim_shebang.vim
new file mode 100755
index 0000000..47a550c
--- /dev/null
+++ b/runtime/syntax/testdir/input/vim_shebang.vim
@@ -0,0 +1,5 @@
+#!/usr/bin/env vim -S
+
+" Vim shebang line
+
+#!/usr/bin/env vim -S