End-of-line comments [tracking issue]

[avh4]

This is a high-level tracking issue for end-of-line comments and having them attach to the back of the previous token instead of being attached the front of the next token.

To be considered:

• if/else branch bodies
• case branch bodies
• (maybe?) tag arguments in types (Tag --z\n a --x\n b --y\n)
• (maybe?) let definition bodies
• (maybe?) top-level definition bodies

Already implemented:

• Allow end-of-line comments #162
  • after record fields in types
  • after record fields in expressions
  • after values in list expressions
  • after values in tuple expressions
  • after entries in tuple types
  • union type definitions
  • after record fields in record updates
  • after record fields in record extension types
  • in function types
  • in binary operator expressions
  • in cons patterns