Document undocumented php prefix option (#14634)

Author: cleptric

docs/platforms/php/common/configuration/options.mdx

@@ -93,6 +93,24 @@ This option can be overridden using `in_app_include`.
 
 </SdkOption>
 
+<SdkOption name="prefixes" type='string[]' defaultValue='[]'>
+
+A list of prefixes that should be stripped from the filenames of captured stacktraces to make them relative. This helps in normalizing file paths across different environments.
+
+For example, if your code is deployed in different locations across environments (e.g., `/var/www/app` in production and `/home/user/projects/app` in development), you can use this option to strip these prefixes and make the paths consistent.
+
+```php
+\Sentry\init([
+    'dsn' => '___DSN___',
+    'prefixes' => [
+        '/var/www/',
+        '/home/user/projects/',
+    ],
+]);
+```
+
+</SdkOption>
+
 <SdkOption name="max_request_body_size"type='string' defaultValue='medium'>
 
 This parameter controls whether integrations should capture HTTP request bodies. It can be set to one of the following values: