Auto merge of #427 - dekellum:package-metadata-docs-rs, r=SimonSapin

Enable rustdoc for feature query_encoding on docs.rs

So that ParseOptions::encoding_override shows up on docs.rs  This relates to and was requested by me in #308.  I believe this is how to implement.

See onur/docs.rs@62fdcf605 for the docs.rs support of this config.

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Author: bors-servo

Cargo.toml

@@ -47,3 +47,6 @@ matches = "0.1"
 percent-encoding = { version = "1.0.0", path = "./percent_encoding" }
 rustc-serialize = {version = "0.3", optional = true}
 serde = {version = ">=0.6.1, <0.9", optional = true}
+
+[package.metadata.docs.rs]
+features = ["query_encoding"]