move specificity hack to the nested plugin docs

Author: kof

docs/jss-plugin-nested.md

@@ -143,6 +143,28 @@ Compiles to:
 }
 ```
 
+## Increase specificity
+
+When extending third party libraries with high secificity selector it's often necessary to also have a high specificity selector.
+
+```javascript
+const styles = {
+  button: {
+    '.button &': {
+      color: 'red'
+    }
+  }
+}
+```
+
+Compiles to:
+
+```css
+.button .button-0 {
+  color: 'red';
+}
+```
+
 ### Demo
 
 [CodeSandbox](//codesandbox.io/s/github/cssinjs/jss/tree/master/examples/plugins/jss-plugin-nested?fontsize=14)

docs/jss-syntax.md

@@ -338,31 +338,6 @@ Compiles to:
 }
 ```
 
-## Specific selectors
-
-When extending third party libraries with high secificity selector it's often necessary to have also have a high specificity.
-
-```javascript
-
-const styles = {
-  button: {
-    '.button &': {
-      color: 'red'
-    }
-  }
-}    
-
-```
-
-Compiles to:
-
-```css
-.button .button-0 {
-  color: 'red'
-}
-```
-
-
 ## Working with colors
 
 You can use any color conversion tool, e.g. [this one](https://yarnpkg.com/en/package/color).