Fix equation label link in proof HTML

Author: douden

tests/test_html/proof/_proof_with_labeled_math.html

@@ -1,5 +1,5 @@
 <div class="proof admonition" id="proof">
 <p>Proof. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut</p>
 <div class="math notranslate nohighlight" id="equation-label1">
-<span class="eqno">(1)<a class="headerlink" href="#equation-label1" title="Link to this equation">¶</a></span>\[P_t(x, y) = \mathbb 1\{x = y\} + t Q(x, y) + o(t)\]</div>
+<span class="eqno">(1)<a class="headerlink" href="#equation-label1" title="Link to this equation"></a></span>\[P_t(x, y) = \mathbb 1\{x = y\} + t Q(x, y) + o(t)\]</div>
 </div>