audio/praat: Update 6.4.23 → 6.4.27, improve port

Changelogs:
https://www.fon.hum.uva.nl/praat/manual/What_s_new_.html

Improve port:
+ Add WWW for source code repository

• State LICENSE=GPLv3+ as on official site [0]
• Sort LIB_DEPENDS
• Remove unneded libraries from LIB_DEPENDS
• Follow upstream switch to C++17 compiler
• Remove unneded any more dos2unix conversion
• Small linting
• Improve pkg-descr

[0] https://www.fon.hum.uva.nl/praat/manual/License.html

PR: 284106
Approved by: adridg (maintainer, timeout > 1 month)