main: consume trailing whitespace in _highlight_list

Fixes highlighting when an unclosed $( ends in whitespace.

highlighters/main/main-highlighter.zsh

@@ -881,7 +881,8 @@ _zsh_highlight_main_highlighter_highlight_list()
     fi
     _zsh_highlight_main_add_region_highlight $start_pos $end_pos $style
   done
-  REPLY=$(( end_pos - 1 ))
+  [[ "$proc_buf" = (#b)(#s)(([[:space:]]|\\$'\n')#) ]]
+  REPLY=$(( end_pos + ${#match[1]} - 1 ))
   reply=($list_highlights)
   return $(( $#braces_stack > 0 ))
 }

highlighters/main/test-data/command-substitution-unclosed.zsh

@@ -41,4 +41,5 @@ expected_region_highlight=(
 
 if [[ ${(z):-'$('} == '$( ' ]]; then # ignore zsh 5.0.8 bug
   expected_region_highlight[2]='3 16 default' # foo$(echo bar
+  expected_region_highlight[3]='6 16 command-substitution-unquoted' # $(echo bar
 fi

highlighters/main/test-data/process-substitution2.zsh

@@ -47,4 +47,5 @@ expected_region_highlight=(
 
 if [[ ${(z):-'$('} == '$( ' ]]; then # ignore zsh 5.0.8 bug
   expected_region_highlight[8]='17 27 default' # =(echo foo
+  expected_region_highlight[9]='17 27 process-substitution' # =(echo foo
 fi

highlighters/main/test-data/quoted-command-substitution-empty.zsh

@@ -28,16 +28,17 @@
 # vim: ft=zsh sw=2 ts=2 et
 # -------------------------------------------------------------------------------------------------
 
-BUFFER='echo "foo$('
+BUFFER='echo "foo$( '
 
 expected_region_highlight=(
   '1 4 builtin' # echo
-  '6 11 default' # "foo$(
+  '6 12 default' # "foo$(
   '6 9 double-quoted-argument-unclosed' # "foo
-  '10 11 command-substitution-quoted' # $(
+  '10 12 command-substitution-quoted' # $(
   '10 11 command-substitution-delimiter-quoted' # $(
 )
 
 if [[ ${(z):-'$('} == '$( ' ]]; then # ignore zsh 5.0.8 bug
-  expected_region_highlight[2]='6 12 default' # "foo$(
+  expected_region_highlight[2]='6 13 default' # "foo$(
+  expected_region_highlight[4]='10 13 command-substitution-quoted' # $(
 fi