Fix for `shellcheck` compliance

cmd

@@ -119,10 +119,10 @@ command_usage() {
   local -a cmds
   for c in "${COMMANDS[@]}"; do
     [[ ${c:0:1} =~ _ ]] && continue
-    cmds+=($c)
+    cmds+=("$c")
   done
-  cmds="${cmds[*]}"
-  printf "usage: %s (%s)\n" "$EXE" "${cmds// /|}"
+  local IFS='|'
+  printf "usage: %s (%s)\n" "$EXE" "${cmds[*]}"
 }
 
 help[help]='
@@ -144,7 +144,7 @@ Also see `readme` and `usage` commands.
 '
 
 command_help() { 
-  local name="${1:-main}" title own body
+  local name="${1:-main}" title body
   title=$(_help_title "$name") || true
   if [[ -z "$title" ]]; then
     body="${help[$name]}"
@@ -152,7 +152,6 @@ command_help() {
     [[ $name = main ]] && title="$EXE"
   else
     body="${help[$name]}"
-    local eol=$'\n'
     body=${body#*$title}
   fi
   local file="/tmp/help-$EXE-$name.html"
@@ -183,14 +182,11 @@ GitHub or similar hosting service.  '
 
 command_readme() {
   _trim "${help[main]}"
-  local usage="$(command_usage)"
-  printf "\n## Commands\n\n"
-  local -a names=("${!help[@]}")
   while IFS= read -r name; do
     [[ $name = main ]] && continue
-    local body=$(_trim "${help[$name]}")
+    body=$(_trim "${help[$name]}")
     [[ $body =~ ^\# ]] || body="# The \`$name\` Command\n\n$body"
-    printf "##$body\n\n"
+    printf "##%s\n\n" "$body"
   done < <(printf "%s\n" "${!help[@]}" | LC_COLLATE=C sort)
   echo -e "----\n\n*Autogenerated $(date)*\n"
 }
@@ -236,7 +232,8 @@ while IFS= read -r line; do
   [[ $line =~ ^declare\ -f\ command_ ]] || continue
   COMMANDS+=( "${line##declare -f command_}" )
 done < <(declare -F)
-COMMANDS=($(LC_COLLATE=C sort < <(printf "%s\n" "${COMMANDS[@]}")))
+mapfile -t COMMANDS < \
+  <(LC_COLLATE=C sort < <(printf "%s\n" "${COMMANDS[@]}"))
 
 if [[ -n $COMP_LINE ]]; then
   line=${COMP_LINE#* }