* add http2 ping checks
* fix test issue
* add h2ping check to config resources
* add new test and docs for h2ping
* fix grammatical inconsistency in H2PING documentation
* resolve rebase conflicts, add test for h2ping tls verification failure
* api documentation for h2ping
* update test config data with H2PING
* add H2PING to protocol buffers and update changelog
* fix typo in changelog entry
* website: migrate to new nav-data format
* website: clean up unused intro content
* website: remove deprecated sidebar_title from frontmatter
* website: add react-content to fix global style import issue
Some TLS servers require SNI, but the Golang HTTP client doesn't
include it in the ClientHello when connecting to an IP address. This
change adds a new TLSServerName field to health check definitions to
optionally set it. This fixes#9473.
