ARROW-11821: [Rust] Edit Rust README
ARROW-11821: [Rust] Edit Rust README

Edits and fixes for some missing words, punctuation, and wording.

Closes #9576 from pierwill/docs-edit

Authored-by: pierwill <a7ab10e8301cd563cb2146de24e8a000ef071fe2@users.noreply.github.com>
Signed-off-by: Andrew Lamb <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@nerdnetworks.org>

apache/arrow,kou/arrow,apache/arrow,laurentgo/arrow,icexelloss/arrow,apache/arrow,kou/arrow,laurentgo/arrow,apache/arrow,laurentgo/arrow,icexelloss/arrow,cpcloud/arrow,wesm/arrow,cpcloud/arrow,wesm/arrow,kou/arrow,kou/arrow,wesm/arrow,apache/arrow,icexelloss/arrow,cpcloud/arrow,laurentgo/arrow,wesm/arrow,cpcloud/arrow,icexelloss/arrow,cpcloud/arrow,apache/arrow,icexelloss/arrow,apache/arrow,kou/arrow,icexelloss/arrow,icexelloss/arrow,wesm/arrow,cpcloud/arrow,cpcloud/arrow,laurentgo/arrow,apache/arrow,cpcloud/arrow,wesm/arrow,apache/arrow,laurentgo/arrow,kou/arrow,wesm/arrow,icexelloss/arrow,laurentgo/arrow,wesm/arrow,apache/arrow,icexelloss/arrow,wesm/arrow,laurentgo/arrow,laurentgo/arrow,cpcloud/arrow,laurentgo/arrow,cpcloud/arrow,wesm/arrow,apache/arrow,kou/arrow,apache/arrow,wesm/arrow,cpcloud/arrow,apache/arrow,wesm/arrow,icexelloss/arrow,icexelloss/arrow,laurentgo/arrow,icexelloss/arrow,cpcloud/arrow,laurentgo/arrow,icexelloss/arrow,laurentgo/arrow,laurentgo/arrow,cpcloud/arrow,kou/arrow,kou/arrow,kou/arrow,icexelloss/arrow,cpcloud/arrow,kou/arrow,kou/arrow,kou/arrow,wesm/arrow,wesm/arrow,apache/arrow,kou/arrow,laurentgo/arrow