Support simple flag in annotate assignment

[Glyphack]

Annotated assignment statements have a flag called simple. This is hardcoded but should be assigned based on the following spec:
https://docs.python.org/3/library/ast.html#ast.AnnAssign

[Glyphack]

Flag is set on this field:

enderpy/parser/src/parser/ast.rs

Line 137 in 4589a3b

pub simple: bool,

Here we need to match lhs agains Name nodes and check if it is inside "()" or not:

enderpy/parser/src/parser/parser.rs

Line 1275 in 4589a3b

target: lhs,

[dwoznicki]

Thanks. I went down a rabbit hole yesterday trying to figure out where lhs gets initialized as an Expression::Name. I figure that's probably not that important, but now I'm curious as I can't seem to follow the stack trace. It must go something like:

parse_assignment_or_expression_statement -> parse_expressions -> parse_expression -> parse_conditional_expression -> ?

EDIT: Nevermind. I printed a backtrace so now I see how this works. The parser "cascades" down through various checks, eventually landing on parse_identifier.

I suppose it might actually be important if we don't track tokens by offset, or some other way to look up a token at a particular index. I'm assuming we don't want to add a surrounded_by_parens or similar field to the Name struct?