runtime(vim): Update base-syntax, improve :map highlighting

Match :map ( RHS properly.

Only match ! after :map, :noremap, :unmap and :mapclear.

closes: #15297

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

runtime/syntax/testdir/input/vim_ex_map.vim

@@ -5,9 +5,6 @@ map! lhs rhs
 map 
 map lhs rhs
 
-call map(list, 'v:val')
-call map (list, 'v:val')
-
 mapclear  <buffer>
 mapclear! <buffer>
 nmapclear <buffer>
@@ -69,6 +66,27 @@ map lhs
 echo "clear"
 
 
+" Differentiate map() from :map
+
+map ( :echo "open-paren"<CR>
+
+call map(list, 'v:val')
+call map (list, 'v:val')
+
+function Foo()
+  map ( :echo "open-paren"<CR>
+  call map(list, 'v:val')
+  call map (list, 'v:val')
+endfunction
+
+def Foo()
+  map ( :echo "open-paren"<CR>
+  map(list, 'v:val')
+  # :map LHS=(list, RHS='v:val')
+  map (list, 'v:val')
+enddef
+
+
 " Issue  #12672
 
 nnoremap <leader>foo :echo call(