Finds and includes more deeply embedded expressions

[markwpearce]

Does not give up so easily when an expression can't be parsed - will continue looking at further expressions.

Examples:

• DottedGetExpressions ending in a . -> first part is parsed as an expression and added to the AST
• CallExpressions -> if there is no closing ), or if an argument is unable to be parsed, the call expression is still added to the AST
• ArrayLiteralExpression if there is no closing ], or if an element is unable to be parsed, the ArrayLiteralExpression is still added to the AST
• etc. (see tests!)

This has the nice side effect of provide WAY more diagnostics - so diagnostics like "Unmatched Bracket" actually show up, instead of "Unexpected newline", as well as being able to provide diagnostics on multiple problem arguments in the same function call.

[TwitchBronBron]

Great PR! I appreciate that it's hyper-focused, and this will be a fantastic improvement to the parser. Just a few suggestions, and then this is good to go.