Add documentation for slide view mode to features page

Since it's a very useful feature, we should mention it in multiple 
locations.

So we mention it in the slide mode section of the features page.

Signed-off-by: Sheogorath <[email protected]>

Author: SISheogorath

public/docs/features.md

@@ -72,9 +72,11 @@ Notes can be embedded as follows:
 
 ## [Slide Mode](./slide-example):
 You can use a special syntax to organize your note into slides.
-After that, you can use the **Slide Mode** <i class="fa fa-tv"></i> to make a presentation.
+After that, you can use the **[Slide Mode](./slide-example)** <i class="fa fa-tv"></i> to make a presentation.
 Visit the above link for details.
 
+To switch the editor into slide mode, set the [document type](./yaml-metadata#type) to `slide`.
+
 View
 ===
 ## Table of Contents: