Docs: add some @since changelog entries

... where relevant.

Author: jrfnl

PHPCSUtils/BackCompat/BCFile.php

@@ -538,6 +538,7 @@ public static function getMethodParameters(File $phpcsFile, $stackPtr)
      *
      * @since 1.0.0
      * @since 1.0.0-alpha2 Added BC support for PHP 7.4 arrow functions.
+     * @since 1.0.0-alpha3 Added support for PHP 8.0 static return type (expected in future PHPCS release).
      *
      * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
      * @param int                         $stackPtr  The position in the stack of the function token to

PHPCSUtils/BackCompat/BCTokens.php

@@ -64,6 +64,7 @@ class BCTokens
      * Token types that are comments containing PHPCS instructions.
      *
      * @since 1.0.0
+     * @since 1.0.0-alpha3 Visibility changed from `protected` to `private`.
      *
      * @var string[]
      */
@@ -79,6 +80,7 @@ class BCTokens
      * Tokens that open class and object scopes.
      *
      * @since 1.0.0
+     * @since 1.0.0-alpha3 Visibility changed from `protected` to `private`.
      *
      * @var array <int|string> => <int|string>
      */
@@ -93,6 +95,7 @@ class BCTokens
      * Tokens that represent text strings.
      *
      * @since 1.0.0
+     * @since 1.0.0-alpha3 Visibility changed from `protected` to `private`.
      *
      * @var array <int|string> => <int|string>
      */

PHPCSUtils/Utils/FunctionDeclarations.php

@@ -176,6 +176,7 @@ public static function getName(File $phpcsFile, $stackPtr)
      *
      * @since 1.0.0
      * @since 1.0.0-alpha2 Added BC support for PHP 7.4 arrow functions.
+     * @since 1.0.0-alpha3 Added support for PHP 8.0 static return type.
      *
      * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
      * @param int                         $stackPtr  The position in the stack of the function token to

PHPCSUtils/Utils/Lists.php

@@ -292,6 +292,8 @@ public static function getOpenClose(File $phpcsFile, $stackPtr, $isShortList = n
      * ```
      *
      * @since 1.0.0
+     * @since 1.0.0-alpha3 The returned value has been simplified with sensible defaults and always
+     *                     available keys.
      *
      * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
      * @param int                         $stackPtr  The position in the stack of the function token