Use rel=prev/next on pagination link

While this is widely documented for SEO reason, it also helps for
accessibility. Notably, if you are using tools like Vimium to browse
using only the keyboard, these hints help to select the links. It's
all the more useful when the text is not in English.

template/html/common/entry_pagination.html

@@ -2,7 +2,7 @@
 <div class="pagination">
     <div class="pagination-prev">
         {{ if .prevEntry }}
-            <a href="{{ .prevEntryRoute }}{{ if .searchQuery }}?q={{ .searchQuery }}{{ end }}" title="{{ .prevEntry.Title }}" data-page="previous">{{ t "pagination.previous" }}</a>
+            <a href="{{ .prevEntryRoute }}{{ if .searchQuery }}?q={{ .searchQuery }}{{ end }}" title="{{ .prevEntry.Title }}" data-page="previous" rel="prev">{{ t "pagination.previous" }}</a>
         {{ else }}
             {{ t "pagination.previous" }}
         {{ end }}
@@ -10,10 +10,10 @@
 
     <div class="pagination-next">
         {{ if .nextEntry }}
-            <a href="{{ .nextEntryRoute }}{{ if .searchQuery }}?q={{ .searchQuery }}{{ end }}" title="{{ .nextEntry.Title }}" data-page="next">{{ t "pagination.next" }}</a>
+            <a href="{{ .nextEntryRoute }}{{ if .searchQuery }}?q={{ .searchQuery }}{{ end }}" title="{{ .nextEntry.Title }}" data-page="next" rel="next">{{ t "pagination.next" }}</a>
         {{ else }}
             {{ t "pagination.next" }}
         {{ end }}
     </div>
 </div>
-{{ end }}
+{{ end }}

template/html/common/pagination.html

@@ -2,7 +2,7 @@
 <div class="pagination">
     <div class="pagination-prev">
         {{ if .ShowPrev }}
-            <a href="{{ .Route }}{{ if gt .PrevOffset 0 }}?offset={{ .PrevOffset }}{{ if .SearchQuery }}&amp;q={{ .SearchQuery }}{{ end }}{{ else }}{{ if .SearchQuery }}?q={{ .SearchQuery }}{{ end }}{{ end }}" data-page="previous">{{ t "pagination.previous" }}</a>
+            <a href="{{ .Route }}{{ if gt .PrevOffset 0 }}?offset={{ .PrevOffset }}{{ if .SearchQuery }}&amp;q={{ .SearchQuery }}{{ end }}{{ else }}{{ if .SearchQuery }}?q={{ .SearchQuery }}{{ end }}{{ end }}" data-page="previous" rel="prev">{{ t "pagination.previous" }}</a>
         {{ else }}
             {{ t "pagination.previous" }}
         {{ end }}
@@ -10,7 +10,7 @@
 
     <div class="pagination-next">
         {{ if .ShowNext }}
-            <a href="{{ .Route }}?offset={{ .NextOffset }}{{ if .SearchQuery }}&amp;q={{ .SearchQuery }}{{ end }}" data-page="next">{{ t "pagination.next" }}</a>
+            <a href="{{ .Route }}?offset={{ .NextOffset }}{{ if .SearchQuery }}&amp;q={{ .SearchQuery }}{{ end }}" data-page="next" rel="next">{{ t "pagination.next" }}</a>
         {{ else }}
             {{ t "pagination.next" }}
         {{ end }}