Fix unicode characters in Puiseux' theorem statement.

[jmadiot]

Thanks! Any reason for K rather than R?

[Zimmi48]

Actually the complete statement is:

puiseux_series_algeb_closed
     : ∀ (α : Type) (R : ring α) (K : field R),
       algeb_closed_field K
       → ∀ pol : polynomial (puiseux_series α),
         degree (ps_zerop K) pol ≥ 1
         → ∃ s : puiseux_series α, (ps_pol_apply pol s = 0)%ps

The statement of the theorem appeared in a section, thus K was not explicitly defined. Daniel de Rauglaudre explained to me that R became K following notation changes. I am going to update the PR.

[jmadiot]

Nice! Thank you.