Accessibility bug in search form template (empty label + missing input id)

Hello WP Responsive Menu team,

I found an accessibility/validation issue in the plugin search form markup.

Plugin: WP Responsive Menu
File: wp-content/plugins/wp-responsive-menu/inc/templates/search-form.php

Issue:
The generated search form uses a label with a for attribute, but the associated input has no matching id, and the label text is empty.

Current output (problematic):

label: for="search-form-..."
input: no id
label content: empty
This triggers validator warning:
Incorrect use of <label for=FORM_ELEMENT>

How to reproduce:

Enable the search box in WP Responsive Menu settings.
Open page source on the frontend.
Locate the form with class wpr-search-form.
You will see an empty label and input without matching id.
Why this matters:

Accessibility: screen readers rely on proper label/input association.
HTML validity: fails validation due to incorrect label usage.
UX quality: semantic form structure is broken.

Suggested fix:
Add a meaningful label text (for example, search placeholder text or a translatable “Search” string).
Add id to the input.
Ensure label for and input id use the same generated unique value.

Example expected structure:
<label for="search-form-UNIQUE_ID" class="screen-reader-text">Search</label>
<input id="search-form-UNIQUE_ID" type="search" ...>

Thank you for checking this.

Best regards
   Uros