chore(docs): remove leading dollar sign

Author: nhedger

README.md

@@ -1494,7 +1494,7 @@ This project follows [SemVer](https://semver.org/).
 This will install the latest supported version:
 
 ```bash
-$ composer require react/socket:^1.11
+composer require react/socket:^1.11
 ```
 
 See also the [CHANGELOG](CHANGELOG.md) for details about version upgrades.
@@ -1542,21 +1542,21 @@ To run the test suite, you first need to clone this repo and then install all
 dependencies [through Composer](https://getcomposer.org/):
 
 ```bash
-$ composer install
+composer install
 ```
 
 To run the test suite, go to the project root and run:
 
 ```bash
-$ vendor/bin/phpunit
+vendor/bin/phpunit
 ```
 
 The test suite also contains a number of functional integration tests that rely
 on a stable internet connection.
 If you do not want to run these, they can simply be skipped like this:
 
 ```bash
-$ vendor/bin/phpunit --exclude-group internet
+vendor/bin/phpunit --exclude-group internet
 ```
 
 ## License