doc: fix label for in catalog search form

The label for "Supported Hardware Capabilities" search field was
pointing to an HTML element with the wrong ID.

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

doc/_extensions/zephyr/domain/templates/board-catalog.html

@@ -60,7 +60,7 @@
   </div>
 
   <div class="form-group" style="flex-basis: 100%">
-    <label for="hw-capabilities">Supported Hardware Capabilities</label>
+    <label for="tag-input">Supported Hardware Capabilities</label>
     <div class="tag-container" id="tag-container">
       <input list="tag-list" class="tag-input" id="tag-input"
              placeholder="{% if hw_features_present -%}