Summary

Part of #3980

This PR starts the implementation of the noSelfAssignment rule. The rule is quite lengthy so I had to stop at sont toless too much meat to the fire.

The implementation of this is quite different from the ESLint one. The ESLint implementation is "simple" but has various pitfalls:

• it relies on recursion
• there's a double loop with recursion

To avoid this memory pressure I had to come up with something, so implementation relies on:

• one single loop
• iterators
• a queue

The gist of the implementation is the following:

• a JsAssignmentExpression is broken in two arms: left-arm and right-arm, which is called AnyJsAssignmentLike
• creates an ad-hoc iterator; this iterator emits similar pairs of "identifiers". If these identifiers are not identical, the loop continues until the iterator is consumed . For example, in a code a = a, it returns the pair of (a, a), but in a code like [a, 1, b] = [a, c, b], the first iteration returns (a, a) but the second iteration return None because 1 and c are not similar (their AST nodes are different), and the third returns (b,b)
• each pair gets checked, and if they have the exact text, they are tracked and then emitted in the diagnostic

The ad-hoc iterator works this way:

• the two arms (left and right) are transformed into two iterators;
• every time we need to compute a new pair of identifiers, we call .next() on both iterators; both items need to exist and need to be "similar" (there are various matches to check if they are similar), failing to adhere to these two requirements will continue to the next item
• every time we find a "substructure" (e.g. object assignment pattern inside an array assignment pattern, for example: [{a, b}, c] = [{a, b}, c], we stop the current iteration, save it into a queue, and we start a new one. We resume the previous one when we "drain" this latest iteration.

This implementation doesn't cover:

• parenthesis
• optional chain
• string literals inside a computed member expression, e.g. a['b']

Test Plan

The tests are taken from the test suite of ESLint

Documentation

• The PR requires documentation
• I will create a new PR to update the documentation