📝 Updates docs with instructions for Material-Design-Icons

docs/icons.md

@@ -14,6 +14,8 @@ Both sections and items can have an icon, which is specified using the `icon` at
   <img width="500" src="https://i.ibb.co/GTVmZnc/dashy-example-icons.png" />
 </p>
 
+Note that, if you are using icons from an external source (like font-awesome or material-design-icons), then the relevant font file will be loaded in automatically if and when needed, but combining icons from multiple services may have a negative impact on performance.
+
 ### Font Awesome
 You can use any [Font Awesome Icon](https://fontawesome.com/icons) simply by specifying it's identifier. This is in the format of `[category] [name]` and can be found on the page for any given icon on the Font Awesome site. For example: `fas fa-rocket`, `fab fa-monero` or `fas fa-unicorn`.
 
@@ -54,7 +56,7 @@ You can use almost any emoji as an icon for items or sections. You can specify t
   <img width="580" src="https://i.ibb.co/YLwgTf9/emoji-icons-1.png" />
 </p>
 
-The following example shows the unicode options available, all three will render the 🚀 emoji.
+The following examples will all render the same rocket (🚀) emoji:
 
 ```yaml
 items:
@@ -74,5 +76,25 @@ You may also want to store your icons locally, bundled within Dashy so that ther
 
 You can also use sub-folders within the `item-icons` directory to keep things organised. You would then specify an icon with it's folder name slash image name. For example: `networking/monit.png`
 
+### Material Design Icons
+Dashy also supports 5000+ [material-design-icons](https://github.com/Templarian/MaterialDesign). To use these, first find the name/ slug for your icon [here](https://dev.materialdesignicons.com/icons), and then prefix is with `mdi-`.
+
+For example:
+```yaml
+sections:
+- name: Material Design Icons Example
+  items:
+  - title: Alien Icon
+    icon: mdi-alien 
+  - title: Fire Icon
+    icon: mdi-fire 
+  - title: Dino Icon
+    icon: mdi-google-downasaur 
+
+```
+
+### Simple Icons
+To use glyphs from [SimpleIcons.org](https://simpleicons.org/), first find the icon slug, and then prefix it with `si-`. The image will be loaded directly from the Simple Icons 
+
 ### No Icon
 If you don't wish for a given item or section to have an icon, just leave out the `icon` attribute.