runtime(vim): Update base syntax, fix :map termination in :command RHS

Ensure :map (and :abbreviate) terminate at | when included in :command
replacement strings containing commands separated by line continuations.

Signed-off-by: Doug Kearns <dougkearns@gmail.com>

runtime/syntax/testdir/input/vim_ex_abbreviate.vim

@@ -1,21 +1,24 @@
 " Vim :abbreviate commands
+" VIM_TEST_SETUP hi link vimMapLhs Identifier
+" VIM_TEST_SETUP hi link vimMapRhs Todo
+" VIM_TEST_SETUP hi link vimMapRhsContinue Todo
 
 
 abbrev <buffer> foo foobar
 cabbrev <buffer> cfoo cfoobar
-iabbrev <buffer> ifoo cfoobar
+iabbrev <buffer> ifoo ifoobar
 
 abbrev <expr> <buffer> foo foobar
 cabbrev <expr> <buffer> cfoo cfoobar
-iabbrev <expr> <buffer> ifoo cfoobar
+iabbrev <expr> <buffer> ifoo ifoobar
 
 noreabbrev <buffer> foo foobar
 cnoreabbrev <buffer> cfoo cfoobar
-inoreabbrev <buffer> ifoo cfoobar
+inoreabbrev <buffer> ifoo ifoobar
 
 abbrev <expr> <buffer> foo foobar
 cabbrev <expr> <buffer> cfoo cfoobar
-iabbrev <expr> <buffer> ifoo cfoobar
+iabbrev <expr> <buffer> ifoo ifoobar
 
 unabbrev <buffer> foo
 cunabbrev <buffer> cfoo
@@ -25,3 +28,27 @@ abclear <buffer>
 cabclear <buffer>
 iabclear <buffer>
 
+
+" Multiline RHS
+
+abbrev foo
+      \ foobar
+
+abbrev foo
+      \
+      \ foobar
+
+abbrev foo
+      "\ comment
+      \ foobar
+
+abbrev foo
+      "\ comment
+      \ foo
+      "\ comment
+      \bar
+
+abbrev lhs
+  "\ comment (matches as RHS but harmless)
+echo "clear"
+