Errors from fuzz testing

[c42f]

Here's a few additional cases which cause parser exceptions found with the tools in #185 / #188 but not yet fixed by the changes there.

• "*>:y", "-<:x" (Fix parsing of chained unary and unary type operators #249)
• "h'?@(g\xfd2)" (Enclose grouping parentheses with parens node #222?)
• "'\\" (fix lexing '\\ to not error in the validate token step #233)
• "@x\"" (Enclose grouping parentheses with parens node #222 etc)
• "1where'c'"
• "@p\"" (Enclose grouping parentheses with parens node #222)
• "@(x y)" (Enclose grouping parentheses with parens node #222)
• "@([x])", "@(x y() \"" (Enclose grouping parentheses with parens node #222)
• "(y::\nfor", "|(&\nfunction"

[c42f]

Ok... so #232 and #236 show that fixing these errors is somewhat higher priority than I thought - several of these are actually cases which are realistic for OhMyREPL users to encounter.