editing 07-high-availability.md (#2172)

* replace passive voice with active as much as possible
* replace "we" and "our" with "you" and "your" as preferred
* some sentence simplification where possible
* fix a couple of spelling issues
* tab content inside of bullet items as preferred (it would not have broken anything to leave them)
* try to put commands and components in back tics as much as possible
* remove conjunctions in favor of full words