minor #35887 [Dotenv] Documentation improvement (jonmldr)

This PR was submitted for the master branch but it was merged into the 4.4 branch instead.

Discussion
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[Dotenv] Documentation improvement

| Q             | A
| ------------- | ---
| Branch?       | 4.4 <!-- see below -->
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| License       | MIT
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Equalization with the component description in the [documentation](https://symfony.com/doc/current/components/dotenv.html).
My suggestion is to remove `getenv()` from this description. [Since Symfony 4.3](https://github.com/symfony/symfony/blob/master/UPGRADE-4.3.md), `$usePutenv = false` by default in `Dotenv::__construct()`. Because of this, `getenv()` is not usable by default.

Commits
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4f61247ccc [Dotenv] Documentation improvement

src/Symfony/Component/Dotenv/README.md

@@ -2,7 +2,7 @@ Dotenv Component
 ================
 
 Symfony Dotenv parses `.env` files to make environment variables stored in them
-accessible via `$_SERVER`, `$_ENV` and optionally `getenv()`.
+accessible via `$_SERVER` or `$_ENV`.
 
 Resources
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