rephrase doc

Author: ZequanWu

lldb/docs/use/variable.rst

@@ -369,12 +369,16 @@ binding mechanism.
 Summary Format Matching On Pointers
 ----------------------
 
-When a summary format is registered for a type ``T``, lldb will apply this
-format to both ``T`` and ``T*``. -p options could prevent lldb from using this
-format to type ``T*``. When -p options is not given, users can use the -d option
-to specify how many layer of pointers can be dereferenced at most when matching
-the format of type ``T`` (default to 1). It should be noted that the value
-object passed to the summary format won't dereferenced at all.
+A summary formatter for a type ``T`` might or might not be appropriate to use
+for pointers to that type. If the formatter is only appropriate for the type and
+not its pointers, use the ``-p`` option to restrict it to match SBValues of type
+``T``. If you want the formatter to also match pointers to the type, you can use
+the ``-d`` option to specify how many pointer layers the formatter should match.
+The default value is 1, so if you don't specify ``-p`` or ``-d``, your formatter
+will be used on SBValues of type ``T`` and ``T*``. If you want to also match
+``T**`` set ``-d`` to 2, etc. In all cases, the SBValue passed to the summary
+formatter will be the matched ValueObject. lldb doesn't dereference the matched
+value down to the SBValue of type ``T`` before passing it to your formatter.
 
 Summary Strings
 ---------------