feat(Tactic/ComputeAsymptotics/Multiseries): non-primitive corecursion for Seq: FriendlyOperation API

[vasnesterov]

This is a continuation of #35072.

This PR adds more API about friendly operations:

• FriendlyOperation.coind: a coinductive principle for proving that operation is friendly
• FriendlyOperationClass.eq_of_bisim: a generalisation of Seq.eq_of_bisim' for proving two sequences are equal.

---

• depends on: feat(Tactic/ComputeAsymptotics/Multiseries): non-primitive corecursion for Seq: FriendlyOperation API #35072

This is a part of the compute_asymptotics tactic (#28291).

[github-actions]

PR summary c00fe67bb4

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ FriendlyOperation.coind
+ FriendlyOperation.coind_comp_friend_left
+ FriendlyOperation.coind_comp_friend_right
+ FriendlyOperation.cons
+ FriendlyOperation.cons_tail
+ FriendlyOperation.destruct_apply_eq_unfold
+ FriendlyOperation.of_dist_le_pow
+ FriendlyOperation.op_cons_head_eq
+ FriendlyOperation.op_head_eq
+ FriendlyOperation.unfold
+ FriendlyOperationClass.eq_of_bisim
+ dist_const_tail_cons_tail_le
+ dist_le_half_iff
+ friendlyOperation_iff_dist_le_dist

You can run this locally as follows

## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.

---

Increase in tech debt: (relative, absolute) = (4.00, 0.00)

Current number	Change	Type
6892	4	backward.isDefEq

Current commit 3e80d44598
Reference commit c00fe67bb4

You can run this locally as

./scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[mathlib-dependent-issues]

This PR/issue depends on:

• feat(Tactic/ComputeAsymptotics/Multiseries): non-primitive corecursion for Seq: FriendlyOperation API #35072
  By Dependent Issues (🤖). Happy coding!