feat(analysis/specific_limits): add `cauchy_seq_of_edist_le_geometric` (#1743)
* feat(analysis/specific_limits): add `cauchy_seq_of_edist_le_geometric`
Other changes:
* Estimates on the convergence rate both in `edist` and `dist` cases.
* Swap lhs with lhs in `ennreal.tsum_coe` and `nnreal.tsum_coe`,
rename accordingly
* Use `(1 - r)⁻¹` instead of `1 / (1 - r)` in `has_sum_geometric`
* Add some docstrings
* Update src/analysis/specific_limits.lean