fix: use relative NavLink hrefs for GitHub Pages routing

Author: lzinga

src/BlazorTextDiff.Web/Shared/NavMenu.razor

@@ -8,17 +8,17 @@
 <div class="@NavMenuCssClass" @onclick="ToggleNavMenu">
     <nav class="flex-column">
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="/" Match="NavLinkMatch.All">
+            <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
                 <span class="bi bi-house-fill" aria-hidden="true"></span> Home
             </NavLink>
         </div>
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="/character-highlight">
+            <NavLink class="nav-link" href="character-highlight">
                 <span class="bi bi-highlighter" aria-hidden="true"></span> Characters
             </NavLink>
         </div>
         <div class="nav-item px-3">
-            <NavLink class="nav-link" href="/async">
+            <NavLink class="nav-link" href="async">
                 <span class="bi bi-cloud-download-fill" aria-hidden="true"></span> Async
             </NavLink>
         </div>