[BUGFIX] Support legacy-mode PSR-autoloading for enum type files

The ClassMapGenerator is used in non-composer ("legacy") mode
installations and builds files used for PSR-autoloading.

It only parsed class|interface|trait files, but not files containing
enum type definitions. Thus, the PSR-autoloading created by this
classmap was not able to autoload these enum files.

The underlying code had been adapted from the Composer libraries
some time in the past, meanwhile that code from Composer was extracted
to the package "composer/class-map-generator" and has drifted from
the current TYPO3 implementation.

That implementation at https://github.com/composer/class-map-generator/blob/953cc4ea32e0c31f2185549c7d216d7921f03da9/src/PhpFileParser.php#L118
supports "enum" class loading in case the PHP version matches.

This patch simply also adds "enum" as a recognized identifier.

Resolves: #102498
Releases: main, 12.4
Change-Id: I1b98e8ceeecd25f1512d3539e84de6c725a8e3c6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82034


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>