Use relativize './search.html'

Closes gh-155

Author: rwinch

src/partials/search.hbs

@@ -7,7 +7,7 @@
                 <div id="searchbox"></div>
                 <div id="counter"></div>
                 <div class="search-by">
-                    <a class="search-link" href="/search.html">Search in all Spring Docs</a>
+                    <a class="search-link" href="{{{relativize './search.html'}}}">Search in all Spring Docs</a>
                     <a target="_blank" rel="noopener noreferrer" href="https://www.algolia.com/" aria-label="Search by Algolia">
                         <img class="light" width="140" src="{{{uiRootPath}}}/img/algolia-light.svg" />
                         <img class="dark" width="140" src="{{{uiRootPath}}}/img/algolia-dark.svg" />