Update C++ standard list of --std option in manpage (#5506)

The manpage only lists up to C++11 and it says C++11 is default. It is
out-of-dated.

man/cppcheck.1.xml

@@ -549,7 +549,7 @@ There are false positives with this option. Each result must be carefully invest
         </term>
         <listitem>
           <para>Set standard. The available options are:
-            <glosslist><glossentry><glossterm>c89</glossterm><glossdef><para>C code is C89 compatible</para></glossdef></glossentry><glossentry><glossterm>c99</glossterm><glossdef><para>C code is C99 compatible</para></glossdef></glossentry><glossentry><glossterm>c11</glossterm><glossdef><para>C code is C11 compatible (default)</para></glossdef></glossentry><glossentry><glossterm>c++03</glossterm><glossdef><para>C++ code is C++03 compatible</para></glossdef></glossentry><glossentry><glossterm>c++11</glossterm><glossdef><para>C++ code is C++11 compatible (default)</para></glossdef></glossentry></glosslist>
+            <glosslist><glossentry><glossterm>c89</glossterm><glossdef><para>C code is C89 compatible</para></glossdef></glossentry><glossentry><glossterm>c99</glossterm><glossdef><para>C code is C99 compatible</para></glossdef></glossentry><glossentry><glossterm>c11</glossterm><glossdef><para>C code is C11 compatible (default)</para></glossdef></glossentry><glossentry><glossterm>c++03</glossterm><glossdef><para>C++ code is C++03 compatible</para></glossdef></glossentry><glossentry><glossterm>c++11</glossterm><glossdef><para>C++ code is C++11 compatible</para></glossdef></glossentry><glossentry><glossterm>c++14</glossterm><glossdef><para>C++ code is C++14 compatible</para></glossdef></glossentry><glossentry><glossterm>c++17</glossterm><glossdef><para>C++ code is C++17 compatible</para></glossdef></glossentry><glossentry><glossterm>c++20</glossterm><glossdef><para>C++ code is C++20 compatible (default)</para></glossdef></glossentry></glosslist>
           </para>
         </listitem>
       </varlistentry>