docs: Remove unnecessary --save in install instructions (TanStack#1149)

* Remove unnecessary --save in install instructions

Thankfully, `--save` hasn't been necessary with NPM for some time now :)

* Update devtools.md

* making uniform with devtools instructions

Author: cryptiklemur

docs/src/pages/docs/devtools.md

@@ -12,7 +12,7 @@ When you begin your React Query journey, you'll want these devtools by your side
 To get going as fast as possible, do the following:
 
 ```bash
-$ npm i --save react-query-devtools
+$ npm i react-query-devtools
 # or
 $ yarn add react-query-devtools
 ```

docs/src/pages/docs/installation.md

@@ -9,14 +9,10 @@ You can install React Query with [NPM](https://npmjs.com),
 
 ### NPM
 
-```sh
-npm install react-query --save
-```
-
-or
-
-```sh
-yarn add react-query
+```bash
+$ npm i react-query
+# or
+$ yarn add react-query
 ```
 
 React Query is compatible with React v16.8+ and works with ReactDOM and React Native.