Remove multi title in doc files

Author: Mathieudewet

core/jwt.md

@@ -7,7 +7,7 @@
 API Platform allows to easily add a JWT-based authentication to your API using [LexikJWTAuthenticationBundle](https://github.com/lexik/LexikJWTAuthenticationBundle).
 To install this bundle, [just follow its documentation](https://github.com/lexik/LexikJWTAuthenticationBundle/blob/master/Resources/doc/index.md).
 
-# Installing LexikJWTAuthenticationBundle
+## Installing LexikJWTAuthenticationBundle
 
 `LexikJWTAuthenticationBundle` requires your application to have a properly configured user provider.
 You can either use the [Doctrine user provider](https://symfony.com/doc/current/security/entity_provider.html) provided

distribution/testing.md

@@ -183,7 +183,7 @@ You may also be interested in these alternative testing tools (not included in t
   test in the CI using [newman](https://github.com/postmanlabs/newman).
 * [PHP Matcher](https://github.com/coduo/php-matcher): the Swiss Army knife of JSON document testing.
 
-# Running Unit Tests with PHPUnit
+## Running Unit Tests with PHPUnit
 
 To run your [PHPUnit](https://phpunit.de/) test suite, execute the following command: