Improvements for switch captures

[FnControlOption]

Fix resolved type of tag capture in inline switch case

const Enum = enum {
    foo,
    bar,
    baz,
    qux,
};

const TaggedUnion = union(Enum) {
    foo: i32,
    bar: bool,
    baz: f64,
    qux: void,
};

const some_tagged_union: TaggedUnion = .{ .baz = 3.14 };

const switch_tagged_union_inline = switch (some_tagged_union) {
    inline .foo => |a, b| .{ a, b },
    //                 ^ Enum
    inline .bar => |a, b| .{ a, b },
    //                 ^ Enum
    inline else => |a, b| .{ a, b },
    //                 ^ Enum
};

Fix resolved type of switch capture for non-enum/union types

const some_u8: u8 = 'e';

const switch_u8 = switch (some_u8) {
    'x' => |a| a,
    //      ^ u8
    'y' => |a| a,
    //      ^ u8
    else => |a| a,
    //       ^ u8
};

Resolve type of else capture in tagged union switch

const switch_tagged_union = switch (some_tagged_union) {
    .foo => |a| a,
    .bar => |a| a,
    else => |a| a,
    //       ^ TaggedUnion
};

[Techatrix]

The test cases should ideally also cover the _ prong on non-exhaustive enums.

const E = enum(u8) {
    foo,
    bar,
    _,
};
const some_enum: E = .foo;
const what = switch (some_enum) {
    .foo, .bar => {},
    _ => |tag| {},
};