'main': Support the "close file descriptor" and "coproc" redirection syntaxes

Part of issue #645.

highlighters/main/main-highlighter.zsh

@@ -1287,8 +1287,12 @@ _zsh_highlight_main_highlighter_highlight_argument()
   done
 
   if (( path_eligible )); then
-    if (( in_redirection )) && [[ $last_arg == *['<>']['&'] && $arg[$1,-1] == <0-> ]]; then
-      base_style=numeric-fd
+    if (( in_redirection )) && [[ $last_arg == *['<>']['&'] && $arg[$1,-1] == (<0->|p|-) ]]; then
+      if [[ $arg[$1,-1] == (p|-) ]]; then
+        base_style=redirection
+      else
+        base_style=numeric-fd
+      fi
     elif _zsh_highlight_main_highlighter_check_path $arg[$1,-1]; then
       base_style=$REPLY
       _zsh_highlight_main_highlighter_highlight_path_separators $base_style

highlighters/main/test-data/redirection-special-cases.zsh

@@ -35,10 +35,10 @@ BUFFER=$'cat <&p; exec {myfd}>&-'
 expected_region_highlight=(
   '1 3 command' # cat
   '5 6 redirection' # <&
-  '7 7 redirection "issue #645 (in part)"' # p
+  '7 7 redirection' # p
   '8 8 commandseparator' # ;
   '10 13 precommand' # exec
   '15 20 named-fd' # {myfd}
   '21 22 redirection' # >&
-  '23 23 redirection "issue #645 (in part)"' # -
+  '23 23 redirection' # -
 )