[clang-format][docs] Fix incorrect 'clang-format 9' option marker

[kuzkry]

Summary

Introduced by 23a5090c6, this style option marker indicated
'clang-format 9', though its respective option was available in
an earlier release.

[kuzkry]

Hi, I've got yet another one. Luckily, nothing wrong with clang-format 10, all were fine. This one was the only option incorrectly marked as clang-format 9.

Note, AllowShortIfStatementsOnASingleLine was introduced by 1b750edda14879a16ce782b3ade3af599bfbb717

[MyDeveloperDay]

LGTM

clang/docs/ClangFormatStyleOptions.rst

.. code-block:: c++
 
       class Foo {
         void f() { foo(); }
       };
       void f() { bar(); }
 
 
 
-**AllowShortIfStatementsOnASingleLine** (``ShortIfStyle``) :versionbadge:`clang-format 9`
+**AllowShortIfStatementsOnASingleLine** (``ShortIfStyle``) :versionbadge:`clang-format 3.3`
   Dependent on the value, ``if (a) return;`` can be put on a single line.
 
   Possible values:
 
   * ``SIS_Never`` (in configuration: ``Never``)
     Never put short ifs on the same line.
 
     .. code-block:: c++

clang/include/clang/Format/Format.h

enum ShortIfStyle : int8_t {
     ///   else {
     ///     return;
     ///   }
     /// \endcode
     SIS_AllIfsAndElse,
   };
 
   /// Dependent on the value, ``if (a) return;`` can be put on a single line.
-  /// \version 9
+  /// \version 3.3
   ShortIfStyle AllowShortIfStatementsOnASingleLine;
 
   /// Different styles for merging short lambdas containing at most one
   /// statement.
   enum ShortLambdaStyle : int8_t {
     /// Never merge lambdas into a single line.
     SLS_None,
     /// Only merge empty lambdas.