Bootstrap: fontawesome in button of a tag.

error

Button icon is small.

<button class="btn btn-postbit me-1 dropdown-toggle" type="button" id="threadOptions" data-bs-toggle="dropdown" aria-expanded="false"><i class="fas fa-cog"></i></button>

I changed code and Problem soloved.
<button class="btn btn-postbit me-1 dropdown-toggle" type="button" id="threadOptions" data-bs-toggle="dropdown" aria-expanded="false">
  <i class="fas fa-cog"></i>
</button>

But I got error that can't fix by above method.

<a rel="prev" href="{$page_url}" data-bs-toggle="tooltip" data-bs-placement="right" title="{$lang->previous} Page" class="pagination_previous flex-shrink-0 flex-grow-0">
	<button type="button" class="btn btn-tertiary" aria-label="Previous Page"><i class="fas fa-long-arrow-alt-left"></i></button>
</a>

<a rel="prev" href="{$page_url}" data-bs-toggle="tooltip" data-bs-placement="right" title="{$lang->previous} Page" class="pagination_previous flex-shrink-0 flex-grow-0">
	<button type="button" class="btn btn-tertiary" aria-label="Previous Page">
		<i class="fas fa-long-arrow-alt-left"></i>
	</button>
</a>

Don't Solve :(