This promotes "and" and "or" from a type of statement to "job
decorators," as a possible prefix on a job. The point is to rationalize
how they interact with && and ||.
In the new world 'and' and 'or' apply to a entire job conjunction, i.e.
they have "lower precedence." Example:
if [ $age -ge 0 ] && [ $age -le 18 ]
or [ $age -ge 75 ] && [ $age -le 100 ]
echo "Child or senior"
end
Prior to this fix, each redirection type was a separate token_type.
Unify these under a single type TOK_REDIRECT and break the redirection
type out into a new sub-type redirection_type_t.
The previous attempt to support newlines after pipes changed the lexer to
swallow newlines after encountering a pipe. This has two problems that are
difficult to fix:
1. comments cannot be placed after the pipe
2. fish_indent won't know about the newlines, so it will erase them
Address these problems by removing the lexer behavior, and replacing it
with a new parser symbol "optional_newlines" allowing the newlines to be
reflected directly in the fish grammar.
