docs: add .svg as valid background extension (#285)

9f2a541

docs/themes/backgrounds.md

@@ -25,15 +25,15 @@ For uploads you can use the built-in file manager. `(Settings > Machine)`
 Just load a background image into your .theme folder and name it `sidebar-background.<extension>`.
 
 | Filename					| sidebar-background	|
-| Valid file extensions		| .jpg, .png and .gif	|
+| Valid file extensions		| .jpg, .png, .gif and .svg	|
 | Recommended image size	| 300x1000px			|
 
 ## Mainview background image
 Upload a background image into your .theme folder and name it `main-background.<extension>`.
 
 | Filename					| main-background		|
-| Valid file extensions		| .jpg, .png and .gif	|
+| Valid file extensions		| .jpg, .png, .gif and .svg	|
 
 **Please note**: By default, the background image is stretched to the entire area.  
 For example, if you want a repeating pattern, you also need to use custom css.
-{: .info}
+{: .info}