Docs: BCTokens: list methods supported

The `BCTokens` class has a `__callStatic()` method to allow for offering methods for all properties from the PHPCS native `Tokens` array, even when they are unchanged.

Using the `@method` tag, it is now documented which methods will magically resolve.

Ref: https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc-tags.md#57-method

Author: jrfnl

PHPCSUtils/BackCompat/BCTokens.php

@@ -40,6 +40,22 @@
  * the token arrays returned by this class.
  *
  * @since 1.0.0
+ *
+ * @method static array blockOpeners()     Tokens that open code blocks.
+ * @method static array booleanOperators() Tokens that perform boolean operations.
+ * @method static array bracketTokens()    Tokens that represent brackets and parenthesis.
+ * @method static array castTokens()       Tokens that represent type casting.
+ * @method static array commentTokens()    Tokens that are comments.
+ * @method static array emptyTokens()      Tokens that don't represent code.
+ * @method static array equalityTokens()   Tokens that represent equality comparisons.
+ * @method static array heredocTokens()    Tokens that make up a heredoc string.
+ * @method static array includeTokens()    Tokens that include files.
+ * @method static array methodPrefixes()   Tokens that can prefix a method name.
+ * @method static array scopeModifiers()   Tokens that represent scope modifiers.
+ * @method static array scopeOpeners()     Tokens that are allowed to open scopes.
+ * @method static array stringTokens()     Tokens that represent strings.
+ *                                         Note that `T_STRINGS` are NOT represented in this list as this list
+ *                                         is about _text_ strings.
  */
 class BCTokens
 {