Be more consistent with use of --features.

Author: nnethercote

collector/benchmarks/README.md

@@ -29,7 +29,7 @@ They mostly consist of real-world crates.
 - **html5ever-0.26.0**: An HTML parser. Stresses macro parsing code.
 - **hyper-0.14.18**: A fairly large crate. Utilizes async/await, and used by
   many Rust programs. The crate uses cargo features to enable large portions of its
-  structure and is built with `--features client,http1,http2,server,stream`.
+  structure and is built with `--features=client,http1,http2,server,stream`.
 - **image-0.24.1**: Basic image processing functions and methods for 
   converting to and from various image formats. Used often in graphics 
   programming.
@@ -39,7 +39,7 @@ They mostly consist of real-world crates.
   Rust programs.
 - **stm32f4-0.14.0**: A crate that has many thousands of blanket impl blocks.
   It uses cargo features to enable large portions of its structure and is
-  built with `--features stm32f410` to have faster benchmarking times.
+  built with `--features=stm32f410` to have faster benchmarking times.
 - **syn-1.0.89**: A library for parsing Rust code. An important part of the Rust
   ecosystem.
 - **unicode-normalization-0.1.19**: Unicode character composition and decomposition
@@ -143,7 +143,7 @@ Rust code being written today.
 - **regex**: See above. This is an older version of the crate.
 - **piston-image**: See above. This is an older version of the `image` crate.
 - **style-servo**: An old version of Servo's `style` crate. A large crate, and
-  one used by old versions of Firefox.
+  one used by old versions of Firefox. Built with `--features=gecko`.
 - **syn**: See above. This is an older version (0.11.11) of the crate.
 - **tokio-webpush-simple**: A simple web server built with a very old version
   of tokio. Uses futures a lot, but doesn't use `async`/`await`.

collector/benchmarks/hyper-0.14.18/perf-config.json

@@ -1,4 +1,4 @@
 {
-  "cargo_opts": "--features client,http1,http2,server,stream",
+  "cargo_opts": "--features=client,http1,http2,server,stream",
   "category": "primary"
 }

collector/benchmarks/style-servo/perf-config.json

@@ -1,5 +1,5 @@
 {
-    "cargo_opts": "--features gecko",
+    "cargo_opts": "--features=gecko",
     "cargo_rustc_opts": "--cap-lints=warn",
     "cargo_toml": "components/style/Cargo.toml",
     "runs": 1,