Detect gibberish copyright #2402

[JonoYang]

This PR adds a gibberish detector to textcode to avoid processing nonsense copyright strings detected from binaries.

[JonoYang]

@pombredanne We are now failing these tests, but I am not sure if these tests are really needed:

https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/test_copyrights_basic.py#L252
https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/test_copyrights_basic.py#L267
https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/test_copyrights_basic.py#L257
https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/test_copyrights_basic.py#L262

[JonoYang]

@pombredanne removing the tests that I linked above, we only fail these data driven tests:

https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/data/copyrights/scilab-Scilab#L67

• an instance of Scilab (c) INRIA-ENPC. was not detected
• c) INRIA-ENPC. is identified as gibberish

https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/data/copyrights/misco4/linux-copyrights/Documentation/networking/arcnet-hardware.txt#L32

• this did not detect Copyright Waterloo Microsystems Inc. 1985
• @Copyright is identified as gibberish

https://github.com/aboutcode-org/scancode-toolkit/blob/2402-detect-gibberish-copyright/tests/cluecode/data/authors/trailing_date#L3C19-L3C59

• Alexander Kanavin <[email protected]> was not detected
• * : commit 3debe362faa62e5b381b880e3ba23aee07c85f6e Author: is detected as gibberish