Make AttributeErrors on erhQL objects as helpful as possible

[evansd]

When a user tries to access an non-existent attribute on an ehrQL object, we should try to make the error as helpful as possible.

There are (at least) two distinct cases here:

1. Typoing the name of an attribute which does exist on the object

Fortunately Python now handles this pretty nicely out-of-the-box and offers suggestions e.g.

$ python -c 'from ehrql.tables.core import patients; patients.date_of_brith'

Traceback (most recent call last):
  File "<string>", line 1, in <module>
AttributeError: 'patients' object has no attribute 'date_of_brith'. Did you mean: 'date_of_birth'?

2. Using an attribute which doesn't exist on this object but does on others

Examples might be calling first_for_patient() on a un-sorted frame, or calling sum_for_patient() on a non-numeric series.

We ought to be able to spot such errors and generate a more helpful error message.

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Extracted from #505