[ty] elide redundant inlay hints for function args (#21365)
This elides the following inlay hints:
```py
foo([x=]x)
foo([x=]y.x)
foo([x=]x[0])
foo([x=]x(...))
# composes to complex situations
foo([x=]y.x(..)[0])
```
Fixes https://github.com/astral-sh/ty/issues/1514
