fix: fix bottom navigation links for prev/next page (#784)

Author: vuejs-jp-bot

themes/vue/layout/page.ejs

@@ -32,12 +32,14 @@
   <% } %>
   <% if (page.type === 'guide') { %>
     <div class="guide-links">
-      <% site.pages.find({ type: page.type, order: page.order - 1 }).each(function (page) { %>
-        <span>← <a href="<%- url_for(page.path) %>"><%- page.title %></a></span>
-      <% }) %>
-      <% site.pages.find({ type: page.type, order: page.order + 1 }).each(function (page) { %>
-        <span style="float: right;"><a href="<%- url_for(page.path) %>"><%- page.title %></a> →</span>
-      <% }) %>
+      <% const lastPage = site.pages.find({ type: page.type, order: { $lt: page.order }}).sort({ order: -1 }).first(); %>
+      <% if (lastPage) { %>
+        <span>← <a href="<%- url_for(lastPage.path) %>"><%- lastPage.title %></a></span>
+      <% } %>
+      <% const nextPage = site.pages.find({ type: page.type, order: { $gt: page.order }}).sort({ order: 1 }).first(); %>
+      <% if (nextPage) { %>
+        <span style="float: right;"><a href="<%- url_for(nextPage.path) %>"><%- nextPage.title %></a> →</span>
+      <% } %>
     </div>
   <% } %>
   <div class="footer">