Add some missing doccomments #3097

Job	Run time
JS unit tests	1m 1s
.NET unit tests (ubuntu-latest)	2m 44s
Build all projects without errors	12m 40s
Build published projects without warnings (Release)	2m 44s
.NET unit tests (windows-2022)	13m 21s
Build published projects without warnings (Debug)	5m 1s
.NET unit tests (macOS-latest)	5m 47s
UI tests (chrome, ubuntu-latest, Production, Default)	13m 45s
UI tests (chrome, windows-2022, Development, Default)	24m 25s
UI tests (firefox, ubuntu-latest, Development, Default)	20m 18s
UI tests (firefox, ubuntu-latest, Production, Default)	17m 57s
UI tests (firefox, ubuntu-latest, Development, ExperimentalFeaturesTests)	19m 31s
UI tests (chrome, ubuntu-latest, Production, ExperimentalFeaturesTests)	15m 20s
	2h 34m 34s

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