Add shortcodes for customizing slides, markdown, HTML

exampleSite/content/home/shortcodes/section.md

@@ -0,0 +1,39 @@
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+weight = 32
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+
+{{% section %}}
+
+## Section shortcode
+
+The `section` shortcode groups slides into a vertical display.
+
+**To continue, use the down arrow or swipe down.**
+
+---
+
+Put the shortcode around the slides you want to group together.
+
+```markdown
+{{%/* section */%}}
+
+## Section slide 1
+
+---
+
+## Section slide 2
+
+{{%/* /section */%}}
+```
+
+Keep scrolling down.
+
+---
+
+## That's it!
+
+Use the right arrow or swipe right to continue.
+
+{{% /section %}}
+
+