[docs] extend config configuration with all options

resources/docs/config-configuration.md

@@ -1,21 +1,270 @@
 ## Provide Config
 
-By default, Rector picks `rector.php` in your root directory as a configuration file. To change that, use `--config` option in CLI run:
+By default, Rector picks `rector.php` in your project root as the configuration file.
+To change that, use:
 
 ```bash
 vendor/bin/rector process --config rector-custom-config.php
 ```
 
+<br>
+
+**Pro tip**: You can see current default values in the Rector config file:
+
+* on Github: [config/config.php](https://github.com/rectorphp/rector-src/blob/main/config/config.php)
+* or locally in: `/vendor/rector/rector/config/config.php`
+
+<br>
+
 ## Spacing and Indents
 
-By default, Rector prints code with 4 spaces indent and unix newline.
-If you have other preference, change it:
+Default formatting is **4 spaces** and **UNIX newlines**.
+You can override:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withIndent(indentChar: ' ', indentSize: 4);
+```
+
+<br>
+
+## Paths to Process
+
+Define which directories or files Rector should refactor:
 
 ```php
 <?php
 
 use Rector\Config\RectorConfig;
 
 return RectorConfig::configure()
-    ->withIndent(indentChar: ' ', indentSize: 4);
+    ->withPaths([
+        __DIR__ . '/src',
+        __DIR__ . '/tests',
+        __DIR__ . '/packages/Domain',
+    ]);
+```
+
+You can also include all the `*.php` files from root directory:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withPaths([
+        __DIR__ . '/src',
+    ])
+    ->withRootFiles();
+```
+
+<br>
+
+## File Extensions
+
+By default, Rector processes only `.php` files. To add more extensions, use:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withFileExtensions(['php', 'phtml']);
+```
+
+<br>
+
+## PHP Version
+
+Rector reads the PHP version from `composer.json`. It's very rate to use different PHP version than one provided by `composer.json`, as it might use newer syntax and break your code. If you still need different version, you can override it manually:
+
+```php
+use Rector\ValueObject\PhpVersion;
+
+return RectorConfig::configure()
+    ->withPhpVersion(PhpVersion::PHP_81);
+```
+
+<br>
+
+## Using Sets
+
+Enable built-in Rector sets:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withPreparedSets(deadCode: true, codeQuality: true);
+```
+
+Check [Levels](/documentation/levels) and [Set List](/documentation/set-lists) for more.
+
+<br>
+
+## Composer-Based Sets
+
+Rector can auto-enable sets based on installed packages:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withComposerBased(
+        symfony: true,
+        doctrine: true,
+        phpunit: true,
+    );
+```
+
+<br>
+
+## Skipping Rules or Paths
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withSkip([
+        __DIR__ . '/src/Legacy/*',
+        __DIR__ . '/tests/Fixtures',
+    ]);
+```
+
+Skip specific rule:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withSkip([
+        SomeRule::class,
+    ]);
+```
+
+Skip rule for specific files:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withSkip([
+        SomeRule::class => [
+            __DIR__ . '/src/SpecialCase.php',
+        ],
+    ]);
+```
+
+<br>
+
+## Parallel Execution
+
+Rector runs in parallel mode by default. You can customize the parallel execution like this:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withParallel(
+        timeoutSeconds: 600,
+        maxNumberOfProcesses: 8,
+        jobSize: 20,
+    );
+```
+
+Or disable:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withoutParallel();
+```
+
+<br>
+
+## Cache & Temp Directories
+
+By default, Rector uses `sys_get_temp_dir() . '/rector_cached_files'` path to store cache files. E.g. to verify if files were changed since last run, to run only on new or changed files. You can customize it:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withCache(__DIR__ . '/var/rector');
+```
+
+
+
+<br>
+
+## Autoloading & Bootstrap
+
+Rector loads project `vendor/autoload.php` by default. In case you don't use composer autoload or some of your `/vendor` dependencies are not loaded, you can include directories:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withAutoloadPaths([
+        __DIR__ . '/lib',
+        __DIR__ . '/vendor/legacy/package/src',
+    ]);
+```
+
+You can also include exact files that contain e.g. constant definitions:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withBootstrapFiles([
+        __DIR__ . '/config/constants.php',
+    ]);
+```
+
+<br>
+
+## PHPStan integration
+
+Rector load `phpstan.neon` and `phpstan.neon.dist` by default if they exist in your project root. Extensions are ignored on purpose, as some of them run project code (e.g. Doctrine) and breaks idea of static analysis. Most extensions do not bring any value to Rector, as Rector works mostly with native type declaration.
+
+Still, there is a way to load PHPStan extension configs, in case they are needed for your specific Rector rule use case:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    ->withPHPStanConfigs([
+        __DIR__ . '/config/custom-phpstan-extension.neon',
+    ]);
+```
+
+<br>
+
+## Symfony Integration
+
+Some [Symfony Rector rules](https://getrector.com/find-rule?activeRectorSetGroup=symfony) require container metadata. Provide Symfony Container to let Rector access services (name and type mostly) and route definitions.
+
+If your Symfony project was not run yet, dump the container first:
+
+```bash
+bin/console debug:container
+```
+
+Use in config:
+
+```php
+use Rector\Config\RectorConfig;
+
+return RectorConfig::configure()
+    // in XML
+    ->withSymfonyContainerXml(
+        __DIR__ . '/var/cache/dev/App_KernelDevDebugContainer.xml'
+    );
+
+    // or PHP (depending on version)
+    ->withSymfonyContainerPhp(
+        __DIR__ . '/var/cache/dev/App_KernelDevDebugContainer.php'
+    );
 ```