markdown: Add support for HTML styling elements

[RemcoSmitsDev]

Follow-up: zed-industries#37264

This PR adds support for all the common HTML styling elements (b, strong, em, i, ins, del).
It also fixes an issue where we would insert an extra paragraph for new line text that resulted in adding a new line inside the markdown.

Before

After

Code example:

<p>some text <b>bold text</b></p>
<p>some text <strong>strong text</strong></p>
<p>some text <i>italic text</i></p>
<p>some text <em>emphasized text</em></p>
<p>some text <del>delete text</del></p>
<p>some text <ins>insert text</ins></p>

<p>Some text <strong>strong text</strong> more text <b>bold text</b> more text <i>italic text</i> more text <em>emphasized text</em> more text <del>deleted text</del> more text <ins>inserted text</ins></p>

<p>some inline text <img src="https://picsum.photos/200/300" alt="Description of image" style="height: 100px" /> asdjkflsadjfl</p>

# Html Tag
<img src="https://picsum.photos/200/300" alt="Description of image" />

# Html Tag with width and height
<img src="https://picsum.photos/200/300" alt="Description of image" width="100" height="200" />

# Html Tag with style attribute with width and height
<img src="https://picsum.photos/200/300" alt="Description of image" style="width: 100px; height: 200px" />

# Normal Tag
![alt text](https://picsum.photos/200/300)

Release Notes:

• Markdown: Added support for HTML styling elements