message: Remove out-dated -S option from the flatc syntax.
  Looks like it's an older syntax for --strict-json which was long-ago removed in
diff: @@ -3,7 +3,7 @@ Using the schema compiler {#flatbuffers_guide_using_schema_compiler}
  Usage:
  - flatc [ GENERATOR OPTIONS ] [ -o PATH ] [ -I PATH ] [ -S ] FILES...
  + flatc [ GENERATOR OPTIONS ] [ -o PATH ] [ -I PATH ] FILES...
  [ -- FILES...]
  The files are read and parsed in order, and can contain either schemas
  