chore: update enums3.rs addressing extra parentheses usage with tuples

[HerschelW]

The circumstances surrounding tuples and additional parentheses are in regard to passing an argument to a function. Otherwise, I could not find any reference stating that extra parentheses indicate a tuple.

If I create a tuple such as let tup = (('a',)) I receive the following warning:

unnecessary parentheses around assigned value '#[warn(unused_parens)] on by default'

Furthermore, if I made an attempt to indicate a tuple with a single element by doing double parentheses
let tup = (('a'))
the rustfmt will automatically remove the extra parentheses and assume I meant to indicate a char type. Similar to Python, the comma after the lone element is what will indicate the value being a tuple. ('a',)

[shadows-withal]

@all-contributors please add @HerschelW for content

[allcontributors]

@diannasoreil

I've put up a pull request to add @HerschelW! 🎉

[vikkio88]

this breaks the exercise tho, it returns this

Progress: [#########>--------------------------------------------------] 15/94 
⚠️  Compiling of exercises/enums/enums3.rs failed! Please try again. Here's the output:
error[E0061]: this enum variant takes 1 argument but 3 arguments were supplied
  --> exercises/enums/enums3.rs:61:23
   |
61 |         state.process(Message::ChangeColor(255, 0, 255));
   |                       ^^^^^^^^^^^^^^^^^^^^
   |
note: tuple variant defined here
  --> exercises/enums/enums3.rs:6:5
   |
6  |     ChangeColor((u8, u8, u8)),
   |     ^^^^^^^^^^^
help: wrap these arguments in parentheses to construct a tuple
   |
61 |         state.process(Message::ChangeColor((255, 0, 255)));
   |                                            +           +

error: aborting due to previous error

For more information about this error, try `rustc --explain E0061`.