Docs: Winged pegasus => Winged Unicorn

[adlerweb]

ponysay/manuals/ponysay.texinfo

Line 1067 in 8a2c714

For Alicorn, Winged pegasus, Pegacorn, etc. like @file{celestia}.

As most pegasi are winged I guess in this context (Alicorn) this should more likely be a winged unicorn.
If not automated ponysay.pdf has to be regenerated also.