Fix `json-par-beginning-of-object-value' at end of one-line object

When the following condition mets, move just after the colon:

* The surrounding object is one-line.
* The value is missing.
* No comments between the colon and the close bracket.

Example:

{ "abc|":  }
↓
{ "abc": | }

where "|" represents the point.

json-par-motion.el

@@ -325,14 +325,22 @@ If PARSED is given, it is used instead of calling
     (json-par--forward-spaces)
     (when (memq (char-after) '(?\] ?\) ?}))
       (goto-char (json-par-token-end (gethash :colon-token parsed)))
-      (skip-chars-forward "\s\t")))
+      (skip-chars-forward "\s\t")
+      (when (memq (char-after) '(?\] ?\) ?}))
+        (goto-char (json-par-token-end (gethash :colon-token parsed)))
+        (when (memq (char-after) '(?\s ?\t))
+          (forward-char)))))
 
    ((gethash :key-token parsed)
     (goto-char (json-par-token-end (gethash :key-token parsed)))
     (json-par--forward-spaces)
     (when (memq (char-after) '(?\] ?\) ?}))
       (goto-char (json-par-token-end (gethash :key-token parsed)))
-      (skip-chars-forward "\s\t")))
+      (skip-chars-forward "\s\t")
+      (when (memq (char-after) '(?\] ?\) ?}))
+        (goto-char (json-par-token-end (gethash :key-token parsed)))
+        (when (memq (char-after) '(?\s ?\t))
+          (forward-char)))))
 
    (t
     (goto-char (gethash :end-of-member parsed)))))