Simplify placeholder pipes documentation

Reference StringFormatter project for modifier details instead of
duplicating documentation.

Assisted-by: Claude Code (Opus 4.5)

Author: henriquemoody

docs/messages/placeholder-pipes.md

@@ -5,27 +5,12 @@ SPDX-License-Identifier: MIT
 
 # Placeholder Pipes
 
-Validation uses [Stringifier](https://github.com/Respect/Stringifier) to convert values into strings for templates. By default, strings get double quotes around them. With placeholder pipes, you can customize how values are rendered by adding a pipe (`|`) followed by the modifier name to your placeholder.
+Validation uses [StringFormatter](https://github.com/Respect/StringFormatter) to render validation messages. Placeholder pipes allow you to customize how values are rendered by adding a pipe (`|`) followed by a modifier name to your placeholder.
 
 ## Usage
 
 To use a placeholder pipe, modify your placeholder like this: `{{placeholder|modifier}}`
 
-```php
-v::templated(
-    'The {{field|raw}} field is required',
-    v::notEmpty(),
-    ['field' => 'email'],
-)->assert('');
-// → The email field is required
-```
-
-## Available Modifiers
-
-### raw
-
-The `raw` modifier removes quotes around values, which is useful for field names or labels that shouldn't look like string values:
-
 ```php
 v::templated(
     'The {{field|raw}} field is required',
@@ -36,60 +21,11 @@ v::templated(
 // (instead of: The "email" field is required)
 ```
 
-### quote
-
-The `quote` modifier uses backticks instead of double quotes, which is great for patterns or code-like values:
-
-```php
-v::templated(
-    'Product SKU must follow the {{pattern|quote}} format',
-    v::regex('/^[A-Z]{3}-\d{4}$/'),
-    ['pattern' => 'XXX-0000'],
-)->assert('invalid-sku');
-// → Product SKU must follow the `XXX-0000` format
-```
-
-### trans
-
-The `trans` modifier translates the value when using a translator:
-
-```php
-v::templated(
-    'Le champ {{field|trans}} est invalide',
-    v::email(),
-    ['field' => 'email_address'], // key in your translation file
-)->assert('not-an-email');
-// → Le champ "adresse e-mail" est invalide
-```
-
-### list:or
-
-The `list:or` modifier formats arrays as readable lists using "or":
-
-```php
-v::templated(
-    'Status must be {{haystack|list:or}}',
-    v::in(['active', 'pending', 'archived']),
-)->assert('deleted');
-// → Status must be "active", "pending", or "archived"
-```
-
-### list:and
-
-The `list:and` modifier formats arrays as readable lists using "and":
-
-```php
-v::templated(
-    'User must have {{roles|list:and}} roles to perform this action',
-    v::callback(fn(User $user) => $user->hasRoles(['admin', 'editor'])),
-    ['roles' => ['admin', 'editor']],
-)->assert($user);
-// → User must have "admin" and "editor" roles to perform this action
-```
+## Available Modifiers
 
-## Combining with Custom Templates
+Validation supports all modifiers from StringFormatter except `StringPassthroughModifier`. For detailed documentation on each modifier, see the [StringFormatter Modifiers documentation](https://github.com/Respect/StringFormatter/blob/main/docs/modifiers/Modifiers.md).
 
-Placeholder pipes work with both inline templates and `Templated` validators:
+## Examples
 
 ```php
 // Using with assert()
@@ -101,20 +37,11 @@ v::templated(
     v::email(),
     ['field' => 'email']
 )->assert($input);
-```
-
-## Nested Validators
 
-Placeholder pipes are particularly useful when working with nested validators:
-
-```php
-v::key('age', v::positive())
-  ->assert($input, [
-    '__root__' => 'Please check your data',
-    'age' => 'The {{name|raw}} field must be {{expected|quote}}'
-  ]);
+// Using list modifiers
+v::templated(
+    'Status must be {{haystack|list:or}}',
+    v::in(['active', 'pending', 'archived']),
+)->assert('deleted');
+// → Status must be "active", "pending", or "archived"
 ```
-
-## Custom Modifiers
-
-At the moment, only the modifiers documented above are officially supported. Support for registering custom placeholder pipes is not part of the public API yet, but you can create your own modifiers.