feat(python): support bytecode translation to map_dict where the lookup key is an expression

[alexander-beedie]

Integrates BINARY_SUBSCR into the generic binary operator translation path so that we can support suggestions where the key is itself an expression.

This enables new suggestions for apply functions that use lookups, such as...

import polars as pl

ascii = { o:chr(o) for o in range(127) }

df = pl.DataFrame({
    "ord": [40,50,60,70,80,90,100,110],
}).with_columns(
    prev_chr = pl.col('ord').apply( lambda x: ascii[x-1] ),
    next_chr = pl.col('ord').apply( lambda x: ascii[x+1] ),
)

...which will now generate the following:

PolarsInefficientApplyWarning: 
Expr.apply is significantly slower than the native expressions API.
Only use if you absolutely CANNOT implement your logic otherwise.
In this case, you can replace your `apply` with the following:
  - pl.col("ord").apply(lambda x: ...)
  + (pl.col("ord") - 1).map_dict(ascii)

PolarsInefficientApplyWarning: 
Expr.apply is significantly slower than the native expressions API.
Only use if you absolutely CANNOT implement your logic otherwise.
In this case, you can replace your `apply` with the following:
  - pl.col("ord").apply(lambda x: ...)
  + (pl.col("ord") + 1).map_dict(ascii)

Also: renamed BytecodeParser's can_rewrite method to can_attempt_rewrite, as we do not know if bytecode containing BINARY_SUBSCR is rewritable until we check frame variables during expression translation.

---

(For the curious...)

df.with_columns(
    chr = pl.col("ord").map_dict(ascii),
    prev_chr = (pl.col("ord") - 1).map_dict(ascii),
    next_chr = (pl.col("ord") + 1).map_dict(ascii),
)
# shape: (8, 4)
# ┌─────┬─────┬──────────┬──────────┐
# │ ord ┆ chr ┆ prev_chr ┆ next_chr │
# │ --- ┆ --- ┆ ---      ┆ ---      │
# │ i64 ┆ str ┆ str      ┆ str      │
# ╞═════╪═════╪══════════╪══════════╡
# │ 40  ┆ (   ┆ '        ┆ )        │
# │ 50  ┆ 2   ┆ 1        ┆ 3        │
# │ 60  ┆ <   ┆ ;        ┆ =        │
# │ 70  ┆ F   ┆ E        ┆ G        │
# │ 80  ┆ P   ┆ O        ┆ Q        │
# │ 90  ┆ Z   ┆ Y        ┆ [        │
# │ 100 ┆ d   ┆ c        ┆ e        │
# │ 110 ┆ n   ┆ m        ┆ o        │
# └─────┴─────┴──────────┴──────────┘

[MarcoGorelli]

truly wonderful