Add missing translate function

[IanDelMar]

This PR:

• Adds a missing translation function.
• Replaces wp_kses_post with wp_kses and an array of allowed HTML (an <a> tag and its href attribute) to ensure translators cannot add additional HTML.
• Replaces esc_attr with esc_url to properly escape the URL, as esc_url is the appropriate function for this purpose.

Question:
Does this repository adhere to a specific coding standard? The code contains a mix of tabs and spaces for indentation, sometimes even on the same line. I would have addressed this for the lines affected by this fix, but I could not find any information about the guidelines, if there are any.