runtime(vim): Update base syntax, allow Vim9 :echo tail comments

- Match comments after Vim9 :echo and :execute.
- Match comments after Vim9 and legacy :eval.

closes: #18420

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

runtime/syntax/testdir/input/vim9_ex_echo.vim

@@ -0,0 +1,36 @@
+vim9script
+# Vim9 :echo commands
+# VIM_TEST_SETUP hi link vimVar Identifier
+
+
+echo         # comment
+echo "Foo"   # comment
+echo foo[0]  # comment
+echo Foo()   # comment
+echo "Foo" | # comment
+
+def Foo()
+  echo         # comment
+  echo "Foo"   # comment
+  echo foo[0]  # comment
+  echo Foo()   # comment
+  echo "Foo" | # comment
+enddef
+
+
+echo "4"
+  # comment
+  .. "2" # comment
+
+echo "4" ..
+  # comment
+  "2" # comment
+
+echo "4" # comment
+  # comment
+  .. "2" # comment
+
+echo "4" .. # comment
+  # comment
+  "2" # comment
+

runtime/syntax/testdir/input/vim_ex_eval.vim

@@ -12,3 +12,9 @@ eval "Foo"->append(0) | echo "Foo"
 
 echo "Foo" | eval "Foo"->append(0)
 
+eval "Foo"->append(0) " comment
+
+def Vim9Context()
+  eval "Foo"->append(0) # comment
+enddef
+

runtime/syntax/testdir/input/vim_ex_execute.vim

@@ -51,6 +51,11 @@ execute| echo "Foo"
 " trailing comment needs |
 execute "Foo" | " comment
 
+def Vim9Context()
+  # trailing comment allowed
+  execute "Foo" # comment
+enddef
+
 
 " Issue #9987 (parenthesised argument - not a function call)