feat(zsh): allow multi selection in man_widget(complete)

When in complete mode, all selection of multiple flags. The flags will
be added to the command link in the order they were selected. If one or
more flags require an argument, one has to add that after the fact.

shell/zsh/man_widget.zsh

@@ -1,12 +1,13 @@
 PREVIEW_SCRIPT=preview_flag_docs
+MODE=""
 
 man-widget() {
-  local mode="complete"
+  MODE="complete"
   local command=($(get-command-from-buffer | xargs))
 
   if [ -z "$command" ]; then
     command=($(select-command | xargs))
-    mode="lookup"
+    MODE="lookup"
   fi
 
   [ -z "$command" ] && return
@@ -19,18 +20,18 @@ man-widget() {
 
   [ -z "$flag" ] && return
 
-  case $mode in
+  case $MODE in
     lookup)
       echo
       # "${PREVIEW_SCRIPT}" "$flag" ${command[@]}
       go-to-docs "$flag" ${command[@]}
       ;;
     complete)
-      add-flag "$flag"
+      add-flags "$flag"
       ;;
   esac
 
-  # zle reset-prompt
+  zle reset-prompt
 }
 
 zle -N man-widget
@@ -58,6 +59,7 @@ select-flag() {
   local command=("$@")
   local preview
   local window
+  local multi
   if command -v "${PREVIEW_SCRIPT}" >/dev/null 2>&1; then
     preview="${PREVIEW_SCRIPT} {} ${command[*]}"
     window='down:70%'
@@ -66,12 +68,18 @@ select-flag() {
     window='down:10%'
   fi
 
+  local fzf_cmd=("fzf")
+  fzf_cmd+=('--preview' "${preview}")
+  fzf_cmd+=('--preview-window' "${window}")
+
+  if [ "$MODE" = "complete" ]; then
+    fzf_cmd+=('--multi')
+  fi
+
   man-or-help ${command[@]} \
     | grep '^[[:blank:]]*-[^ ]' \
     | sed -e 's/^[[:blank:]]*//' -e '/^---/d' \
-    | fzf \
-    --preview "${preview}" \
-    --preview-window "${window}" \
+    | "$fzf_cmd[@]" \
     | strip-to-only-flag
 }
 
@@ -109,6 +117,12 @@ strip-to-only-flag() {
   cut -d ',' -f1 | cut -d ' ' -f1
 }
 
+add-flags() {
+  for flag in ${=1}; do
+    add-flag "$flag"
+  done
+}
+
 add-flag() {
   if [ "${LBUFFER: -1}" = " " ]; then
     LBUFFER="${LBUFFER}$1"