Improve handling of filtration output in print method

[astamm]

tdaunif::sample_2sphere(
  n = 100,
  sd = 0.05
) |> 
  TDA::alphaComplexDiag() |> 
  getElement("diagram") |>
  as_persistence()

outputs

── Persistence Data ────────────────────────────────────────
ℹ There are 100, 103, and 9 pairs in dimensions 0, 1, and 2 respectively.
ℹ Computed from a Alphacomplex filtration using `TDA::alphaComplexDiag()`.
! With unknown parameters.

where we would expect:

• no capitalisation;
• a space between alpha and complex;
• an instead of a in front of alpha;

Similarly, no capitalisation should be done for cubical.