[Validator] Update "ltrim" and "rtrim" options in the Length constraint page

Author: renan-taranto

reference/constraints/Length.rst

@@ -133,30 +133,6 @@ max
 This required option is the "max" length value. Validation will fail if
 the given value's length is **greater** than this max value.
 
-ltrim
-~~~~~
-
-**type**: ``boolean``  **default**: ``null``
-
-If ``true``, every kind of whitespace from the **beginning** of the given value
-will be ignored while checking for its length.
-
-rtrim
-~~~~~
-
-**type**: ``boolean``  **default**: ``null``
-
-If ``true``, every kind of whitespace from the **end** of the given value will
-be ignored while checking for its length.
-
-mergeConsecutiveWhitespaces
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-**type**: ``boolean``  **default**: ``null``
-
-If ``true``, consecutive whitespaces will count as a single character while
-checking for the given value's length.
-
 charset
 ~~~~~~~
 
@@ -191,4 +167,5 @@ exactMessage
 The message that will be shown if min and max values are equal and the underlying
 value's length is not exactly this value.
 
+.. include:: /reference/constraints/_ltrim-rtim-options.rst.inc
 .. include:: /reference/constraints/_payload-option.rst.inc

reference/constraints/_ltrim-rtim-options.rst.inc

@@ -0,0 +1,17 @@
+ltrim
+~~~~~
+
+**type**: ``boolean``  **default**: ``false``
+
+If ``true``, then the :phpfunction:`ltrim` PHP function will be used in order to
+ignore leading whitespace characters in the given value while checking if it is
+valid.
+
+rtrim
+~~~~~
+
+**type**: ``boolean``  **default**: ``false``
+
+If ``true``, then the :phpfunction:`rtrim` PHP function will be used in order to
+ignore trailing whitespace characters in the given value while checking if it is
+valid.