Add Scaladoc comments to all code in language & passes modules

Pull Request Test Coverage Report for Build 8917312703

67 of 111 (60.36%) changed or added relevant lines in 15 files are covered.
113 unchanged lines in 37 files lost coverage.
Overall coverage increased (+0.002%) to 70.796%

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
hugo/src/main/scala/com/ossuminc/riddl/hugo/GlossaryPass.scala	0	1	0.0%
hugo/src/main/scala/com/ossuminc/riddl/hugo/ToDoListPass.scala	0	1	0.0%
hugo/src/main/scala/com/ossuminc/riddl/hugo/writers/EntityWriter.scala	0	1	0.0%
language/src/main/scala/com/ossuminc/riddl/language/parsing/HandlerParser.scala	1	2	50.0%
passes/src/main/scala/com/ossuminc/riddl/passes/resolve/ResolutionPass.scala	2	3	66.67%
language/src/main/scala/com/ossuminc/riddl/language/Messages.scala	6	8	75.0%
passes/src/main/scala/com/ossuminc/riddl/passes/symbols/SymbolsPass.scala	2	4	50.0%
passes/src/main/scala/com/ossuminc/riddl/passes/validate/ValidationPass.scala	0	2	0.0%
prettify/src/main/scala/com/ossuminc/riddl/prettify/PrettifyPass.scala	0	2	0.0%
language/src/main/scala/com/ossuminc/riddl/language/AST.scala	51	82	62.2%
<!--	Total:	67	111	60.36%	-->

Files with Coverage Reduction	New Missed Lines	%
language/src/main/scala/com/ossuminc/riddl/language/At.scala	1	83.87%
prettify/src/main/scala/com/ossuminc/riddl/prettify/PrettifyState.scala	1	60.61%
commands/src/main/scala/com/ossuminc/riddl/commands/PrettifyCommand.scala	1	94.74%
commands/src/main/scala/com/ossuminc/riddl/commands/FromCommand.scala	1	88.89%
testkit/src/main/scala/com/ossuminc/riddl/testkit/RunPassTestBase.scala	1	71.43%
language/src/main/scala/com/ossuminc/riddl/language/parsing/ProjectorParser.scala	1	88.89%
language/src/main/scala/com/ossuminc/riddl/language/parsing/SagaParser.scala	1	88.24%
language/src/main/scala/com/ossuminc/riddl/language/parsing/DomainParser.scala	1	89.47%
hugo/src/main/scala/com/ossuminc/riddl/hugo/utils/TreeCopyFileVisitor.scala	1	66.67%
passes/src/main/scala/com/ossuminc/riddl/passes/validate/DefinitionValidation.scala	1	60.55%
<!--	Total:	113	-->