This removes the ASDL code generation in favor of handwriting the AST.
The motivations for moving away from the ASDL are:
* CPython compatibility is no longer a goal
* The ASDL grammar isn't as expressive as we would like
* The codegen scripts have a high complexity which makes extensions time
consuming
* We don't make heavy use of code generation (compared to e.g.
RustPython that generates Pyo3 bindings, a fold implementation etc).
We may want to revisit a grammar based code generation in the future,
e.g. by using [ungrammar](https://github.com/rust-analyzer/ungrammar)
This adds the missing implementation of `Ranged` for `TextRange` itself
```rust
impl Ranged for TextRange {
fn range(&self) -> TextRange {
*self
}
}
```
This allows e.g. using `has_comments` with arbitrary ranges instead of
just a node.
It also adds .venv to the .gitignore
In the example below, `arg` is `&Expr`, so `&Ranged`, but `entries()`
want a `T: Ranged`. This adds the missing bridge impl.
```rust
let all_args = format_with(|f| {
f.join_comma_separated()
.entries(
// We have the parentheses from the call so the arguments never need any
args.iter()
.map(|arg| (arg, arg.format().with_options(Parenthesize::Never))),
)
.nodes(keywords.iter())
.finish()
});
```
## Summary
This PR adds `TextRange` to `Identifier`. Right now, the AST only
includes ranges for identifiers in certain cases (`Expr::Name`,
`Keyword`, etc.), namely when the identifier comprises an entire AST
node. In Ruff, we do additional ad-hoc lexing to extract identifiers
from source code.
One frequent example: given a function `def f(): ...`, we lex to find
the range of `f`, for use in diagnostics.
Another: `except ValueError as e`, for which the AST doesn't include a
range for `e`.
Note that, as an optimization, we avoid storing the `TextRange` for
`Expr::Name`, since it's already included.
