control log output: decorations (#2097)
control log output: decorations (#2097)

* logdecorations

* Update logdecorations.md

* examples

* typo

* missed

* changes

* clarify

* add existing decorations

* feedbackl

* startgroup

* typo

* feedback

* typo

* abt display

* remove implicit
Microsoft/vsts-agent,Microsoft/vsts-agent,Microsoft/vsts-agent,Microsoft/vsts-agent