push-to-pull-request: Accept intermixed options and arguments again.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

tools/push-to-pull-request

@@ -27,8 +27,10 @@ EOF
 }
 
 merge=
+args=()
 
-while getopts ":-:" opt; do
+while ((OPTIND <= $#)); do
+    if getopts ":-:" opt; then
         case $opt in
             -)
                 case "$OPTARG" in
@@ -50,9 +52,13 @@ while getopts ":-:" opt; do
                 exit 1
                 ;;
         esac
+    else
+        args+=("${!OPTIND}")
+        ((OPTIND++))
+    fi
 done
 
-shift $((OPTIND - 1))
+set -- "${args[@]}"
 
 remote_default="$(git config zulip.zulipRemote || echo upstream)"
 pseudo_remote="$(git config zulip.prPseudoRemote || echo)"