feat(analysis/normed_space/operator_norm): a few more estimates (#2233)
* feat(*): a few more theorems about `unique` and `subsingleton`
* Fix compile, fix two non-terminate `simp`s
* Update src/topology/metric_space/antilipschitz.lean
This lemma will go to another PR
* feat(analysis/normed_space/operator_norm): a few more estimates
* `le_op_norm_of_le` : `∥x∥ ≤ c → ∥f x∥ ≤ ∥f∥ * c`;
* `norm_id` → `norm_id_le`, new `norm_id` assumes `∃ x : E, x ≠ 0`
* estimates on the norm of `e : E ≃L[𝕜] F`` and `e.symm`.
* rename `(anti)lipschitz_with.to_inverse` to `to_right_inverse`
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>