runtime(vim): Update base syntax, match :terminal command

Match the full :terminal command syntax.

closes: #18367

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/input/vim_ex_terminal.vim

@@ -0,0 +1,69 @@
+" Vim :terminal command
+" VIM_TEST_SETUP hi link vimTerminalCommand Todo
+
+
+terminal
+terminal ++kill=term tail -f /tmp/log
+terminal ++hidden ++open make
+
+
+" line continuations
+
+terminal ++kill=term ++hidden tail
+      \ -f
+      \ /tmp/log
+terminal ++kill=term ++hidden
+      \ tail
+      \ -f
+      \ /tmp/log
+terminal ++kill=term
+      \ ++hidden
+      \ tail
+      \ -f
+      \ /tmp/log
+terminal
+      \ ++kill=term
+      \ ++hidden
+      \ tail
+      \ -f
+      \ /tmp/log
+terminal
+      "\ comment
+      \ ++kill=term
+      "\ comment
+      \ ++hidden
+      "\ comment
+      \ tail
+      "\ comment
+      \ -f
+      "\ comment
+      \ /tmp/log
+
+
+" all options
+
+terminal ++close ++noclose ++open ++curwin ++hidden ++norestore ++shell ++kill=term ++rows=42 ++cols=42 ++eof=exit ++type=conpty ++api=Tapi_ tail -f /tmp/log
+terminal
+      \ ++close
+      \ ++noclose
+      \ ++open
+      \ ++curwin
+      \ ++hidden
+      \ ++norestore
+      \ ++shell
+      \ ++kill=term
+      \ ++rows=42
+      \ ++cols=42
+      \ ++eof=exit
+      \ ++type=conpty
+      \ ++api=Tapi_
+      \ tail
+      \ -f
+      \ /tmp/log
+
+
+" escaped option prefix ++
+
+terminal \++close
+terminal ++close \++noclose
+