text: re-adding Chrf implementation

[Borda]

This reverts commit 663f06d.

What does this PR do?

re-adding Chrf temp drooped in #2668 & reopen #2697

Hold for:

• Waiting on @m-popovic to approve it... 🦩

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• Did you make sure to update the docs?
• Did you write any new necessary tests?

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---

📚 Documentation preview 📚: https://torchmetrics--2701.org.readthedocs.build/en/2701/

[codecov]

Codecov Report

Attention: Patch coverage is 85.53459% with 23 lines in your changes missing coverage. Please review.

Project coverage is 39%. Comparing base (ef22554) to head (b5e4559).
Report is 107 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (ef22554) and HEAD (b5e4559). Click for more details.

HEAD has 152 uploads less than BASE

Flag	BASE (ef22554)	HEAD (b5e4559)
Windows	8	3
python3.8	8	3
cpu	58	20
torch1.13.1+cpu	9	3
macOS	11	4
python3.10	15	5
torch2.0.1	6	2
torch2.0.1+cpu	9	3
torch1.12.1+cpu	3	1
Linux	39	13
python3.9	27	9
torch1.10.2+cpu	3	1
torch1.11.0+cpu	3	1
python3.11	8	3
torch2.4.0	3	1
torch2.3.1+cpu	6	2
torch2.1.2+cpu	3	1
torch2.2.2+cpu	6	2
torch2.4.0+cu121	3	1
torch2.4.0+cpu	2	1
torch1.13.1	2	1

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #2701     +/-   ##
========================================
- Coverage      69%     39%    -29%     
========================================
  Files         316     316             
  Lines       17745   17897    +152     
========================================
- Hits        12185    7025   -5160     
- Misses       5560   10872   +5312     

[m-popovic]

I approve re-implementation of chrF under Apache licence

[lantiga]

Thank you @m-popovic! I suggest we reintroduce the code with a clear note that says that

• the code is derived from [link to repo]
• the original author and copyright holder has agreed to relicense the derived code as Apache 2.0 [+ link to this conversation]

Let's avoid retaining mentions of the GPL license explicitly in our source code here, as automated scanners may still flag it.

[lantiga]

Looks good, thanks again @m-popovic

for reference: #2665
cc @kkoehncke