Add math render codeblock and math shortcode.

layouts/_default/_markup/render-codeblock-math.html

@@ -0,0 +1,6 @@
+{{ .Page.Store.Set "math" true -}}
+<p{{ with .Attributes.class }} class="{{ . }}"{{ end }}>
+$$
+{{ .Inner }}
+$$
+</p>

layouts/_default/baseof.html

@@ -10,7 +10,7 @@
 {{ partial "meta_json_ld.html" . }}
 {{ partial "scripts.html" . }}
 {{ partialCached "tracking.html" . }}
-{{ if $.Param "math" }}{{ partialCached "math.html" . }}{{ end -}}
+{{ partialCached "math.html" . }}
 </head>
 
 <body class="{{ if .IsPage }}single-page{{ else }}list-page{{ end }}{{ if .IsHome }} front{{ end }}{{ with $.Param "bodyclass" }} {{ . }}{{ end }}">

layouts/partials/math.html

@@ -1,5 +1,7 @@
+{{ if or ($.Param "math") (.Page.Store.Get "math") (.HasShortcode "math") -}}
 <link rel="stylesheet" href="{{ "katex/katex.min.css" | relURL }}">
 <script defer src="{{ "katex/katex.min.js" | relURL }}"></script>
 <script defer src="{{ "katex/contrib/auto-render.min.js" | relURL }}"></script>
 {{ $math := resources.Get "js/math.js" | minify | fingerprint -}}
 <script defer src="{{ $math.RelPermalink }}"></script>
+{{ end -}}

layouts/shortcodes/math.html

@@ -0,0 +1 @@
+${{ .Inner }}$