docs: add docs for dark variant of a color scheme

docs/editor/code_editor.md

@@ -27,4 +27,9 @@ As of now, only [Java code actions](./java_code_actions.md) are available.
 <details>
     <summary>See location of code actions item in text actions window</summary>
     <img src="../images/editor_code_actions_item.png" width="250"/>
-</details>
+</details>
+
+## Color schemes
+
+You can define your own color schemes that can be used in the editor. The color schemes are defined with JSON files. [Learn more](./color_schemes.md) about how to
+define your own color schemes.

docs/editor/color_schemes.md

@@ -24,10 +24,26 @@ $HOME/.androidide/ui/editor/schemes
     └── scheme.prop
 ```
 
+### Dark variants
+
+Dark variant of a color scheme can be defined by simply creating another color
+scheme with its id suffixed with `-dark`. For example :
+
+```
+$HOME/.androidide/ui/editor/schemes
+├── default  <-- 'default' color scheme
+|   ├── ...
+|   └── scheme.prop
+|
+└── default-dark  <-- Dark variant of 'default' color scheme
+    ├── ...
+    └── scheme.prop
+```
+
 ## Scheme props
 
 The `scheme.prop` file contains basic information about the color scheme such as the scheme name,
-version, etc. This is the file that is first read by the IDE get
+version, etc. This is the file that is first read by the IDE to get
 information about the color scheme. The supported properties are :
 
 ```properties