[reese]

Closes #922

(Note: I'd suggest reviewing with whitespace hidden, as much of the diff in format_prism.rs is just wrapping callers with with_formatting_context.)

Eliding parens inside of certain syntactical constructs changes argument binding or otherwise causes syntax errors. In particular, there's a distinction between callers which allow for command-style calls (raise "foo") and those which require primary expressions, i.e. expressions which are self-enclosing.

This PR wraps several of callers with additional formatting context to prevent the removal of parentheses for special-cased names (describe, it, raise, etc.) when they're in positions that require parens, such as in the middle of argument lists, call chains, and so forth.