Given two strings `s` and `goal`, return `true` if you can swap two letters in `s` so the result is equal to `goal`, otherwise, return `false`.

Swapping letters is defined as taking two indices `i` and `j` (0-indexed) such that `i != j` and swapping the characters at `s[i]` and `s[j]`.

- For example, swapping at indices `0` and `2` in `"abcd"` results in `"cbad"`.

Example 1:

    Input: s = "ab", goal = "ba"
    Output: true
    Explanation: You can swap s[0] = 'a' and s[1] = 'b' to get "ba", which is equal to goal.

Example 2:

    Input: s = "ab", goal = "ab"
    Output: false
    Explanation: The only letters you can swap are s[0] = 'a' and s[1] = 'b', which results in "ba" != goal.

Example 3:

    Input: s = "aa", goal = "aa"
    Output: true
    Explanation: You can swap s[0] = 'a' and s[1] = 'a' to get "aa", which is equal to goal.

Constraints:

- `1 <= s.length, goal.length <= 2 * 104`
- `s` and `goal` consist of lowercase letters.