feat: Add `help-circle` icon

Closes #15, closes #158

icons/help-circle.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M9.09,9a3,3,0,0,1,5.83,1c0,2-3,3-3,3" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/><circle cx="12" cy="12" r="10" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/><line x1="12" y1="17" x2="12" y2="17" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/></svg>
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