[ refactor ] Use smart consS instead of :# subst constructor.

consS (var n) $ wkS (n+1) IdS  optimizes to  wkS n IdS.
[ imports ] Always import Agda.Syntax.Common as Common.
[ Issue 1374 ] Fixed.  Invalid substitution was used in debug output.
Merge branch 'maint-2.4.2'
[ refactor ] Always import Agda.Syntax.Common as Common
Merge branch 'maint-2.4.2'

Conflicts:
	src/full/Agda/Compiler/Epic/Erasure.hs
	src/full/Agda/Compiler/Epic/ForceConstrs.hs
[ Issue 1375 ] Fixed by more precise SIZELT analysis of clauseTel.

TODO: Make analysis even more precise.
[ Issue 1375 ] Variations on a test case.
[ testsuite ] Silenced succeed/Issue1345 (no debug output!).
Merge branch 'maint-2.4.2'
[ issue 1293 ] Cosmetic changes
[ issue 1293 ] Show instance not used any more when reporting errors.

The instance is

  instance Show a => Show (Position' (Maybe a))

from Agda.Syntax.Position.
[ issue 1293 ] Added TODO
[ issue 1293 ] Replaced show function by pretty
Merge remote-tracking branch 'my-agda/issue-1293'

Conflicts:
	src/full/Agda/TypeChecking/Errors.hs
Merge remote-tracking branch 'upstream/master'