docs: Fix relative navigation links (#29468)

Release Notes:

- N/A

Author: osyvokon

docs/theme/index.hbs

@@ -205,13 +205,13 @@
                     <div class="nav-wrapper">
                       <div class="nav-buttons">
                         {{#previous}}
-                          <a rel="prev" href="{{ path_to_root }}/{{link}}" class="nav-button" title="{{title}}" aria-label="Previous chapter">
+                          <a rel="prev" href="{{ path_to_root }}{{link}}" class="nav-button" title="{{title}}" aria-label="Previous chapter">
                             <i class="fa fa-angle-left"></i>
                           </a>
                         {{/previous}}
 
                         {{#next}}
-                          <a rel="next" href="{{ path_to_root }}/{{link}}" class="nav-button" title="{{title}}" aria-label="Next chapter">
+                          <a rel="next" href="{{ path_to_root }}{{link}}" class="nav-button" title="{{title}}" aria-label="Next chapter">
                             <i class="fa fa-angle-right"></i>
                           </a>
                         {{/next}}