Opt out -Zrustdoc-scrape-examples on docs.rs

I'd like a chance to audit all the code that rustdoc is inserting into
the docs. Currently I am skeptical that showing trybuild's internal
usages of APIs is a net benefit to the public documentation. I am also
skeptical that quite so many examples are needed, and that they should
be featured so prominently in comparison to handwritten docs. Lastly I
wish there were a way to turn this behavior off on a more granular
basis.

Cargo.toml

@@ -28,5 +28,8 @@ serde_json = "1.0"
 termcolor = "1.0.4"
 toml = "0.5.2"
 
+[lib]
+doc-scrape-examples = false
+
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]