Tracker: Support all type guards from Pyright

[yangdanny97]

Describe the Bug

From https://microsoft.github.io/pyright/#/type-concepts-advanced?id=type-guards

Type guards of the form x.y or x[y] are all partially-supported: we currently apply the narrowing to the type of x[y], but do not narrow the type of x (if it's something that can be discriminated by that field/index/key)

• x is None / x is not None
• x == None / x != None
• x is ... / x is not ... / x == ... / x != ... (where ... is an ellipsis token) Note: as far as I can tell, this is just for narrowing object or Any to Ellipsis
• x is S / x is not S (where S is a Sentinel) Note: Sentinel here seems to refer to some Final variable - even if S is not a literal, if it is final we can use it for type narrowing.
• type(x) is T / type(x) is not T Type narrowing via assert type(x) is X and assert type(x) == X #335
• type(x) == T / type(x) != T Type narrowing via assert type(x) is X and assert type(x) == X #335
• x is L / x is not L (where L is an expression that evaluates to a literal type)
• x is C / x is not C (where C is a class)
• x == L / x != L (where L is an expression that evaluates to a literal type)
• x.y is None / x.y is not None (where x is a type that is distinguished by a field with a None)
• x.y is E / x.y is not E (where E is a literal enum or bool and x is a type that is distinguished by a field with a literal type) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• x.y == LN / x.y != LN (where LN is a literal expression or None and x is a type that is distinguished by a field or property with a literal type) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• x[K] == V / x[K] != V / x[K] is V / x[K] is not V (where K and V are literal expressions and x is a type that is distinguished by a TypedDict field with a literal type) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• x[I] == V / x[I] != V (where I and V are literal expressions and x is a known-length tuple that is distinguished by the index indicated by I) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• x[I] is B / x[I] is not B (where I is a literal expression, B is a bool or enum literal, and x is a known-length tuple that is distinguished by the index indicated by I) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• x[I] is None / x[I] is not None (where I is a literal expression and x is a known-length tuple that is distinguished by the index indicated by I) [feature] Discriminated Union (narrow typed dicts based on field type) #418
• len(x) == L, len(x) != L, len(x) < L, etc. (where x is tuple and L is an expression that evaluates to an int literal type)
• x in y / x not in y (where y is instance of list, set, frozenset, deque, tuple, dict, defaultdict, or OrderedDict)
• S in D / S not in D (where S is a string literal and D is a TypedDict) TypedDict NotRequired key narrowing #84
• isinstance(x, T) (where T is a type or a tuple of types)
• issubclass(x, T) (where T is a type or a tuple of types)
• f(x) (where f is a user-defined type guard as defined in PEP 647 or PEP 742)
• bool(x) (where x is any expression that is statically verifiable to be truthy or falsey in all cases)
• x (where x is any expression that is statically known to be truthy or falsy)

Sandbox Link

No response

(Only applicable for extension issues) IDE Information

No response