Finish overhaul; fix code/non-code formatting and other edits: * use host instead of subdomain when referring to host on a route * remove domainexample (app_domain_different)
Finish overhaul; fix code/non-code formatting and other edits:
* use host instead of subdomain when referring to host on a route
* remove domainexample (app_domain_different)

cwest/docs-dev-guide,logit-io/docs-dev-guide,cloudfoundry/docs-dev-guide,shalako/docs-dev-guide,krujos/docs-dev-guide,summerzhao/docs-dev-guide,bridgetkromhout/docs-dev-guide