Fix deprecation error about markup type mmark on example sites

exampleSite/content/post/math-typesetting.md

@@ -3,7 +3,6 @@ author: Hugo Authors
 title: Math Typesetting
 date: 2019-03-08
 description: A brief guide to setup KaTeX
-markup: mmark
 math: true
 ---
 

exampleSiteMultilingual/content/post/math-typesetting.md

@@ -3,7 +3,6 @@ author: Hugo Authors
 title: Math Typesetting
 date: 2019-03-08
 description: A brief guide to setup KaTeX
-markup: mmark
 math: true
 ---
 

exampleSiteMultilingual/content/post/math-typesetting.pl.md

@@ -0,0 +1,45 @@
+---
+author: Hugo Authors
+title: Math Typesetting
+date: 2019-03-08
+description: A brief guide to setup KaTeX
+math: true
+---
+
+Mathematical notation in a Hugo project can be enabled by using third party JavaScript libraries.
+<!--more-->
+
+In this example we will be using [KaTeX](https://katex.org/)
+
+- Create a partial under `/layouts/partials/math.html`
+- Within this partial reference the [Auto-render Extension](https://katex.org/docs/autorender.html) or host these scripts locally.
+- Include the partial in your templates like so:  
+
+```
+{{ if or .Params.math .Site.Params.math }}
+{{ partial "math.html" . }}
+{{ end }}
+```  
+- To enable KaTex globally set the parameter `math` to `true` in a project's configuration
+- To enable KaTex on a per page basis include the parameter `math: true` in content files.
+
+**Note:** Use the online reference of [Supported TeX Functions](https://katex.org/docs/supported.html)
+{{< math.inline >}}
+{{ if or .Page.Params.math .Site.Params.math }}
+<!-- KaTeX -->
+<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.10.1/dist/katex.min.css" integrity="sha384-dbVIfZGuN1Yq7/1Ocstc1lUEm+AT+/rCkibIcC/OmWo5f0EA48Vf8CytHzGrSwbQ" crossorigin="anonymous">
+<script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.1/dist/katex.min.js" integrity="sha384-2BKqo+exmr9su6dir+qCw08N2ZKRucY4PrGQPPWU1A7FtlCGjmEGFqXCv5nyM5Ij" crossorigin="anonymous"></script>
+<script defer src="https://cdn.jsdelivr.net/npm/katex@0.10.1/dist/contrib/auto-render.min.js" integrity="sha384-kWPLUVMOks5AQFrykwIup5lo0m3iMkkHrD0uJ4H5cjeGihAutqP0yW0J6dpFiVkI" crossorigin="anonymous" onload="renderMathInElement(document.body);"></script>
+{{ end }}
+{{</ math.inline >}}
+
+### Examples
+
+Inline math: $$ \varphi = \dfrac{1+\sqrt5}{2}= 1.6180339887… $$
+
+Block math:
+
+$$
+ \varphi = 1+\frac{1} {1+\frac{1} {1+\frac{1} {1+\cdots} } } 
+$$
+