fix: include manifest URL on all pages

BREAKING CHANGE:
If overriding icon.png, rename it to icon-32.png and add icon-512.png.

Fix #1245
See #1247

layouts/partials/site_head.html

@@ -138,12 +138,9 @@
   <link rel="alternate" href="{{.RelPermalink}}" type="application/rss+xml" title="{{site.Title}}">
   {{ end }}
 
-  {{ range .AlternativeOutputFormats }}
-  <link rel="{{.Rel}}" type="{{.MediaType.Type}}" href="{{.RelPermalink | safeURL}}">
-  {{ end }}
-
-  <link rel="icon" type="image/png" href="{{ "/img/icon.png" | relURL }}">
-  <link rel="apple-touch-icon" type="image/png" href="{{ "/img/icon-192.png" | relURL }}">
+  <link rel="manifest" href="{{ "index.webmanifest" | relURL }}">
+  <link rel="icon" type="image/png" href="{{ "img/icon-32.png" | relURL }}">
+  <link rel="apple-touch-icon" type="image/png" href="{{ "img/icon-192.png" | relURL }}">
 
   <link rel="canonical" href="{{ .Permalink }}">
 

layouts/slides/baseof.html

@@ -10,8 +10,8 @@
   <meta name="generator" content="Source Themes Academic {{ site.Data.academic.version }}">
 
   <link rel="manifest" href="{{ "index.webmanifest" | relURL }}">
-  <link rel="icon" type="image/png" href="{{ "/img/icon.png" | relURL }}">
-  <link rel="apple-touch-icon" type="image/png" href="{{ "/img/icon-192.png" | relURL }}">
+  <link rel="icon" type="image/png" href="{{ "img/icon-32.png" | relURL }}">
+  <link rel="apple-touch-icon" type="image/png" href="{{ "img/icon-192.png" | relURL }}">
 
   <link rel="canonical" href="{{ .Permalink }}">