docs: fix grammar in outlier detection doc (#11971)
docs: fix grammar in outlier detection doc (#11971)

Fixes grammar errors and does minor rephrasing to improve how the Outlier detection architecture doc reads.

Risk Level: low
Testing: N/A
Docs Changes: grammar
Release Notes: N/A

Signed-off-by: Martin Matusiak <805e7797cf7f6cadfe7e6285068651d2ddf767e1@gmail.com>
lyft/envoy,lyft/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,lyft/envoy,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,lizan/envoy,lizan/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,lyft/envoy,lyft/envoy