[ clean ] Removed excessive commented-out imports, ordered imports.
[ clean ] Removed excessive indentation, fixed some comments.
[ opt ] noRange instead of killRange Range in Syntax.Info.
[ clean ] Removed unused alternative ExprInfo.ExprSource.
[ clean ] Removed old copattern-related code from Abstract.Syntax.
[ comment ] Ren in Syntax.Abstract.
[ Makefile ] make -C ... library-test  should now work.
[ comments ] Haddocumentation for Syntax.Abstract.Expr.
[ refactor ] overloaded fold Syntax.Abstract.allNames.

Use instances instead of name variants.
[ new ] Generic fold for Syntax.Abstract.Expr.
[ new ] new constructor Syntax.Abstract.Expr.Proj.

Future use: instead of Def for projection names.
[ clean ] removed old commented-out code from TC.Rules.Term.
[ debug ] Reactivated debug message in Rules.Term.
[ refactor ] Translate concrete projections to A.Proj instead of A.Def.
[ Issue 1288 ] Updated test/lib-succeed/Issue846.
Merge branch 'maint-2.4.2' of github.com:agda/agda into maint-2.4.2