Fix docs

Author: ai

README.md

@@ -126,15 +126,15 @@ You can define this mixins in `mixins` option.
 
 This type is ideal for CSS hacks or business logic.
 
-Also you should use function mixin if you need to change property names
+Also, you should use function mixin if you need to change property names
 in mixin, because [postcss-simple-vars] doesn’t support variables
 in properties yet.
 
 First argument will be `@mixin` node, that called this mixin.
 You can insert your declarations or rule before or after this node.
 Other arguments will be taken from at-rule parameters.
 
-See [PostCSS API] about nodes API.
+See [PostCSS API](https://postcss.org/api/) about nodes API.
 
 ```js
 require('postcss-mixins')({
@@ -351,8 +351,8 @@ module.exports = {
 Type: `string|string[]`
 
 Similar to [`mixinsDir`](#mixinsdir); except, you can provide
-[tinyglobby](https://github.com/SuperchupuDev/tinyglobby) syntax to target or not target
-specific files.
+[tinyglobby](https://github.com/SuperchupuDev/tinyglobby) syntax
+to target or not target specific files.
 
 ```js
 require('postcss-mixins')({