Markdown UDL does not affect strikethrough

Description of the Issue

When using either of the Markdown UDLs (dark or light) and using the strikethrough format like so:
~~strikethrough~~
which comes out in this Github post editor (which supports Markdown) as:
strikethrough
Using it in Notepad++ with either UDL selected has no effect.

Steps to Reproduce the Issue

1. Set language to Markdown
2. Type the following:
   
3. As can be seen, there is no visual effect added to the strikethrough text.

Expected Behavior

Perhaps a line would be drawn through the text, or at least the color would change, probably to red.

Actual Behavior

There was no effect.

Debug Information

Notepad++ v8.1.8 (64-bit)
Build time : Oct 19 2021 - 16:59:18
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Command Line :
Admin mode : ON
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 10 Home (64-bit)
OS Build : 17134.0
Current ANSI codepage : 1252
Plugins : mimeTools.dll NppConverter.dll NppExport.dll

Source: https://docs.github.com/en/github/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax. This document mentions the strikethrough format for markdown.

Start by locating the dark and light Markdown UDL definitions used by Notepad++; compare their handling of ~~...~~ with the reported GitHub Markdown behavior. Update the relevant UDL configuration so strikethrough is visibly distinguished, then verify it in Notepad++ using the reproduction steps.