A precedence annotation wrapping a sequence of characters now only affects how
tightly those characters bind to *each other*, not how tightly they bind to the
preceding character.
This bug surfaced because a generated lexer was failing to recognize a '\n' character
as a token, instead treating it as ubiquitous whitespace. It made this error
because, even though anonymous ubiquitous tokens have the lowest precedence, the
character immediately *after* the '\n' was part of a normal token, which had
*normal* precedence (0). Advancing into that following token was incorrectly
prioritized above accepting the line-break token.
The parser is no longer hard-coded to skip whitespace. Tokens
such as newlines, whose characters overlap with the separator
characters, can now be correctly recognized.
