fix: fixes for emphasis obj

[stevenxxiu]

Checklist

• Used only camelCase variable names.
• If functionality is added or modified, also made respective changes to the readme.
• Used conventional commits keywords.

This PR stops matching spaces at the start or end of the content string. It stops selecting the middle part * * in the following case:

*a* *b*

The other commit also applies to M.anyQuote().

With the document with the cursor at the end, press yiq. Then an extra character l gets written.

foo|

[chrisgrieser]

thx.

Btw, if you regularly make PRs, you might wanna setup stylua, so the formatting is consistent with the rest of the plugin. (not gonna hold up your PRs due to this, but it's easier in the long run)

[stevenxxiu]

Good idea, thanks.