feature: the paredit-wrap-around now support to select sexp at point without the need to move point to the beginning of sexp

[sakurawald]

This pr does improve the implementation for paredit-wrap-around in buffer-mark-p = nil branch.

The pr contains:

1. Simplify the impl by re-use the forward-sexp and backward-sexp funciton. (The end is where the forward-sexp point at, the start is where the backward-sexp point at.)
2. Remove the handling of following-space. (It's handled by backward-sexp, after the eval of backward-sexp, the current-point are guarantee to at the first char of sexp.)
3. Support to select the sexp at current point as a whole unit.
4. Always insert 1 space before the first char of sexp, and move current-point at it. (Now it's more smooth to chain-call functions, the space is inserted there.)
5. Treat the open char, string between open-char and closed-char and closed char as the same form. (Fix issue like: The level in paired open-parenthesis and closed-parenthesis is not identical. #1612)

---

Let's asume your current-point is inside the word second, the paredit-wrap can now treat the second as a whole sexp, without the need to move current-point to the ( or first-char of sexp

Before this pr

After this pr