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## Summary
Our `SoftKeywordTokenizer` only respected soft keywords in compound
statement positions -- for example, at the start of a logical line:
```python
type X = int
```
However, type aliases can also appear in simple statement positions,
like:
```python
class Class: type X = int
```
(Note that `match` and `case` are _not_ valid keywords in such
positions.)
This PR upgrades the tokenizer to track both kinds of valid positions.
Closes https://github.com/astral-sh/ruff/issues/8900.
Closes https://github.com/astral-sh/ruff/issues/8899.
## Test Plan
`cargo test`
## Summary
This PR fixes the bug in the lexer where the `Mode::Ipython` wasn't
being considered when initializing the soft keyword transformer which
wraps the lexer. This means that if the source code starts with either
`match` or `type` keyword, then the keywords were being considered as
name tokens instead. For example,
```python
match foo:
case bar:
pass
```
This would transform the `match` keyword into an identifier if the mode
is `Ipython`.
The fix is to reverse the condition in the soft keyword initializer so
that any new modes are by default considered as the lexer being at start
of line.
## Test Plan
Add a new test case for `Mode::Ipython` and verify the snapshot.
fixes: #8870
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## Summary
This PR removes the `Interactive` and `FunctionType` parser modes that are unused by ruff
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## Test Plan
`cargo test`
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