Review the differences between `algo.map()` and `expr.map()`

[s-leroux]

Review the differences between algo.map() and expr.map():

https://github.com/s-leroux/fin/blob/78913aa0820239ea5d4d7ccbc37ccecc176a4e61/fin/seq/algo.py#L562-L573

https://github.com/s-leroux/fin/blob/78913aa0820239ea5d4d7ccbc37ccecc176a4e61/fin/seq/expr.py#L18-L19

Check if:

• we can merge both of them
• or rename one or the other to avoid confusion

[s-leroux]

Is this still an issue with the new sequence implementation introduced with v0.2.0?