DartDocs for `Pipeline` is broken.

[renatoathaydes]

trafficstars

From Pipeline class:

/// Note: this package also provides `addMiddleware` and `addHandler` extensions
//  members on [Middleware], which may be easier to use.
class Pipeline {

Notice the final line in the docs starts with //, not ///. So it doesn't show up in the docs.

[devoncarew]

Good catch! Interested in sending a PR for it?

[renatoathaydes]

I will do that in exchange for you guys also letting me fix https://github.com/dart-lang/shelf/issues/270.

Deal?

[devoncarew]

Fixing #270 seems reasonable; @kevmoo and @natebosch would be good reviewers for any PR for that. If the fix will be non-trival, you might want to discuss the solution in that issue, just so you can know ahead of time whether it's something we think we can accept.