Fix function harness options

Change one description and add pointers-as-strings description.

Author: Petr Bauch

src/goto-harness/function_harness_generator_options.h

@@ -48,8 +48,11 @@ Author: Diffblue Ltd.
   "                              set the parameter <size_name> to the size"    \
   " of\n                              the array <array_name>\n"                \
   "                              (implies "                                    \
-  "-- " FUNCTION_HARNESS_GENERATOR_ASSOCIATED_ARRAY_SIZE_OPT                   \
+  "-- " FUNCTION_HARNESS_GENERATOR_TREAT_POINTER_AS_ARRAY_OPT                  \
   " <array_name>)\n"                                                           \
+  "--" FUNCTION_HARNESS_GENERATOR_TREAT_POINTER_AS_CSTRING                     \
+  " p    treat the function parameter with the name `p' as\n"                  \
+  "                              a string of characters\n"                     \
   // FUNCTION_HARNESS_GENERATOR_HELP
 
 // clang-format on