Various edits to the Docker file suggested by Docker

Author: pavpanchekha

Dockerfile

@@ -4,14 +4,14 @@
 
 # Build image
 # Builds output under /herbie/egg-herbie
-FROM rust:1.61.0 as egg-herbie-builder
+FROM --platform=linux/amd64 rust:1.61.0 AS egg-herbie-builder
 WORKDIR /herbie
 COPY egg-herbie egg-herbie
 RUN cargo build --release --manifest-path=egg-herbie/Cargo.toml
 
 # Production image
-FROM racket/racket:8.13-full AS production
-MAINTAINER Pavel Panchekha <[email protected]>
+FROM --platform=linux/amd64 racket/racket:8.13-full AS production
+LABEL maintainer="Pavel Panchekha <[email protected]>"
 COPY --from=egg-herbie-builder /herbie/egg-herbie /src/egg-herbie
 RUN raco pkg install /src/egg-herbie
 COPY src /src/herbie

www/doc/2.1/docker.html

@@ -147,7 +147,7 @@ <h2>Building the Docker image</h2>
 
   <pre class="shell">docker run -p 8000:80 -it uwplse/herbie:test</pre>
 
-  <p>The web demo should now be visiable at <code>http://localhost:8000</code>.</p>
+  <p>The web demo should now be visible at <code>http://localhost:8000</code>.</p>
 
   <p>To open a shell in a running container for testing, first get the container ID with:</p>