Improve basic HTML support in app descriptions

Currently the following code

<p>
	<b>Currently supported App sources:</b>
</p>
<ul>
	<li>
		<p>Open Source - General:</p>
		<ul>
			<li>GitHub</li>
			<li>GitLab</li>
			<li>Forgejo (Codeberg)</li>
			<li>F-Droid</li>
			<li>Third Party F-Droid Repos</li>
			<li>IzzyOnDroid</li>
			<li>SourceHut</li>
		</ul>
	</li>

is displayed as:

Because of this, developers still find it easier to format their app descriptions as plain text instead of using a unified style for listings. The latter would make the descriptions of the catalog applications more consistent in style and more professional.

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Mozilla Firefox 145.0b4