Trailing doc comments

[bharrisau]

Not sure if this is big enough for a RFC, or if it is unwanted as it adds to the problem in #6782.

In Zinc, we have been trialling a different doc comment syntax to make marking up our struct-like macros a little nicer (https://github.com/hackndev/zinc/blob/master/ioreg/ioreg.rs#L129).

The //= attaches to the previous field, such that

struct Foo {
  foo1: bool, //= Doc comment
  foo2: bool  //= Doc comment2
}

is the same as

struct Foo {
  /// Doc comment
  foo1: bool,
  /// Doc comment 2
  foo2: bool
}

Something to consider?

[steveklabnik]

It would need an RFC, and we already have six kinds of comment. Not sure another one is worth it.

[steveklabnik]

Yes, please persue an RFC if you'd still like to try to get this into Rust.