[12.x] Allow validator message placeholers to be capitalized

[florianraith]

Extend placeholder capitalization beyond :attribute to other validator placeholders (e.g., :other in the same rule). This makes behavior consistent across placeholders and improves localization for languages such as German, where field names are typically capitalized.

// Example 'same' => 'The :Attribute field must match :Other.', // Before: "The Password field must match :Other." // After: "The Password field must match Password confirmation."

This PR addresses the inconsistency where :Attribute was supported, but other placeholders (like :Other) were not.

The implementation is inspired by FormatMessages::replaceAttributePlaceholder() which implements the feature for :attribute

[shaedrich]

Would it make sense to move that logic to its own method and then reuse it?

private function replaceKeepCase($message, $placeholder, $parameter) { $fn = [ Str::lower(...), Str::upper(...), Str::ucfirst(...) ]; $cases = array_map(fn (callable $fn) => ':' . $fn($placeholder), $fn); $replacements = array_map(fn (callable $fn) => $fn($parameter), $fn); return str_replace($cases, $replacements, $message); } protected function replaceAcceptedIf($message, $attribute, $rule, $parameters) { $parameters[1] = $this->getDisplayableValue($parameters[0], Arr::get($this->data, $parameters[0])); $parameters[0] = $this->getDisplayableAttribute($parameters[0]); return $this->replaceKeepCase( $this->replaceKeepCase($message, 'other', $parameters[0]), 'value', $parameters[1],	); }