OPENNLP-1520 - Re-Generate Snowball Stemmer Java Code

[rzo1]

For all changes:

• Is there a JIRA ticket associated with this PR? Is it referenced
  in the commit message?

• Does your PR title start with OPENNLP-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.

• Has your PR been rebased against the latest commit within the target branch (typically main)?

• Is your initial contribution a single, squashed commit?

For code changes:

• Have you ensured that the full suite of tests is executed via mvn clean install at the root opennlp folder?
• Have you written or updated unit tests to verify your changes?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE file, including the main LICENSE file in opennlp folder?
• If applicable, have you updated the NOTICE file, including the main NOTICE file found in opennlp folder?

For documentation related changes:

• Have you ensured that format looks appropriate for the output in which it is rendered?

Note:

• Regenerates the Snowball Stemmer Java Code with the latest changes from https://github.com/snowballstem/snowball
• It is based upon 867c4ec70debd4daa7fb4d5a9f7759b47887d0b9 (which has a neat fix for German ;-) )
• Adds a test case for Finish, which triggered the issue described in OPENNLP-1520 in the old generated code.

Possible follow-up issue(s):

• Include https://github.com/snowballstem/snowball-data/tree/master in our eval data and run our stemmers against this beautiful dataset
• Include other language stemmers like Yiddish, Basque, etc.
• Add a README.md and describe how to re-generate the stemmer code.

[rzo1]

Thx for review @mawiesne

[atarora]

Wow , looks so much cleaner !! Thanks for the great work @rzo1 !!

[jonmv]

Nicely done, and much quicker than I'd hoped for! Thanks, on behalf of all of our (and your) users!