Improve readme + Update doc links (#64)

README.md

@@ -17,21 +17,20 @@
 
 The package provides common internationalization utilities:
 
-- `Locale` stores locale information created from BCP 47 formatted string.
-  It can parse locale string, modify locale parts,
-  form locale string from parts, and derive fallback locale.
+- `Locale` stores locale information created from [BCP 47](https://www.rfc-editor.org/info/bcp47) formatted string. It
+  can parse locale string, modify locale parts, form locale string from parts, and derive fallback locale.
 - `LocaleProvider` is a stateful service that stores current locale.
 
 ## Requirements
 
-- PHP 7.4 or higher.
+- PHP 8.0 or higher.
 
 ## Installation
 
 The package could be installed with composer:
 
 ```shell
-composer install yiisoft/i18n --prefer-dist
+composer install yiisoft/i18n
 ```
 
 ## General usage

src/Locale.php

@@ -9,7 +9,7 @@
 /**
  * Locale stores locale information created from BCP 47 formatted string.
  *
- * @link https://tools.ietf.org/html/bcp47
+ * @link https://www.rfc-editor.org/info/bcp47
  */
 final class Locale implements \Stringable
 {
@@ -107,7 +107,7 @@ final class Locale implements \Stringable
      *
      * @param string $localeString BCP 47 formatted locale string.
      *
-     * @link https://tools.ietf.org/html/bcp47
+     * @link https://www.rfc-editor.org/info/bcp47
      *
      * @throws InvalidArgumentException
      */
@@ -444,7 +444,7 @@ public function withPrivate(?string $private): self
     }
 
     /**
-     * @link https://tools.ietf.org/html/bcp47
+     * @link https://www.rfc-editor.org/info/bcp47
      *
      * @return string Regular expression for parsing BCP 47.
      * @psalm-return non-empty-string