DOC add links in README

Author: leszekhanusz

README.md

@@ -36,9 +36,10 @@ The main features of GQL are:
 
 * Execute GraphQL queries using [different protocols](https://gql.readthedocs.io/en/latest/transports/index.html) (http, websockets, ...)
 * Possibility to [validate the queries locally](https://gql.readthedocs.io/en/latest/usage/validation.html) using a GraphQL schema provided locally or fetched from the backend using an instrospection query
-* Supports GraphQL queries, mutations and subscriptions
+* Supports GraphQL queries, mutations and [subscriptions](https://gql.readthedocs.io/en/latest/usage/subscriptions.html)
 * Supports [sync or async usage](https://gql.readthedocs.io/en/latest/async/index.html), [allowing concurrent requests](https://gql.readthedocs.io/en/latest/advanced/async_advanced_usage.html#async-advanced-usage)
 * Supports [File uploads](https://gql.readthedocs.io/en/latest/usage/file_upload.html)
+* [gql-cli script](https://gql.readthedocs.io/en/latest/gql-cli/intro.html) to execute GraphQL queries from the command line
 
 ## Installation
 

docs/usage/validation.rst

@@ -3,7 +3,7 @@
 Schema validation
 =================
 
-It a GraphQL schema is provided, gql will validate the queries locally before sending them to the backend.
+If a GraphQL schema is provided, gql will validate the queries locally before sending them to the backend.
 If no schema is provided, gql will send the query to the backend without local validation.
 
 You can either provide a schema yourself, or you can request gql to get the schema