Fix multi-line comments for cpp enums (#5345) (#5346)

- fix CSharp comments generation
- fix Python comments generation
- fix Lua comments generation
- fix PHP comments generation
- fix Dart comments generation
- add brief description of Color enum
- add multi-line comments to the Monster:Color

tests/monster_test_generated.rs

@@ -163,12 +163,16 @@ pub mod example {
   extern crate flatbuffers;
   use self::flatbuffers::EndianScalar;
 
+/// Composite components of Monster color.
 #[allow(non_camel_case_types)]
 #[repr(u8)]
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 pub enum Color {
   Red = 1,
+  /// \brief color Green
+  /// Green is bit_flag with value (1u << 1)
   Green = 2,
+  /// \brief color Blue (1u << 3)
   Blue = 8,
 
 }