email.utils.decode_params not supporting params that contain hyphens

Bug report

Bug description:

The decode_params function from email.utils is failing to combine the parameters from multiple lines if the name of the parameter includes a hyphen "-". Maybe it's this regex which is too strict: https://github.com/python/cpython/blob/9d1e668e6f40967dda5cbb1ce298bf0dff2d807c/Lib/email/utils.py#L392-L393

The decode_params function always ignores the first 2-tuple but the first parameter in a SMTP header can already be a multiline parameter. I don't see a reason why the first array element is skipped here:
https://github.com/python/cpython/blob/9d1e668e6f40967dda5cbb1ce298bf0dff2d807c/Lib/email/utils.py#L398-L405

my code to reproduce:

from email.utils import decode_params

decode_params([('parameter-name*0*',"utf-8''start;"),("parameter-name*1*","-middle-;"),("parameter-name*2*","end;")])
# parameter-name is not combined:
#  [('parameter-name*0*', "utf-8''start;"), ('parameter-name*1*', '"-middle-;"'), ('parameter-name*2*', '"end;"')]

decode_params([('parametername*0*',"utf-8''start;"),("parametername*1*","-middle-;"),("parametername*2*","end;")])
# parametername is combined but not the first 2-tuple:
# [('parametername*0*', "utf-8''start;"), ('parametername', (None, None, '"-middle-;end;"'))]

decode_params([("ignored","ignored"),('parametername*0*',"utf-8''start;"),("parametername*1*","-middle-;"),("parametername*2*","end;")])
# parametername is now combined as expected, the additional entry can be ignored when processing the output
# [('ignored', 'ignored'), ('parametername', ('utf-8', '', '"start;-middle-;end;"'))]

Thank you
Michael

CPython versions tested on:

3.12

Operating systems tested on:

Linux

Linked PRs

• gh-153536

Lib/email/utils.py の decode_params から始め、参照されている正規表現の周辺と、初期タプルの処理におけるパラメーター名のパースを調べてください。issue にある 3 つの例を再現し、その後、リンクされている PR gh-153536 と動作を比較してください。既存のケースを後退させることなく、ハイフンを含むパラメーター名と最初の複数行パラメーターが一貫して処理されれば完了です。