Found following issues in docs.

1. Broken links: 404 error in below path:
   File: https://github.com/envoyproxy/envoy/blob/master/PULL_REQUESTS.md
   section: Runtime guard -> contributing doc link.

2. Typos in below path:
   File : https://www.envoyproxy.io/docs/envoy/latest/start/sandboxes/fault_injection
   Step-3 - > Terminal-2 Section
   Typo in : Fauilt injection is configured in Evoy but turned off (i.e. affects 0% of requests).