[ issue 1269 ] Added type signatures

Also cosmetic changes and changes suggested by HLint 1.9.5.
[ issue 1269 ] Fixed

The function TypeChecking.Primitive.primQNameType returns a normalised
type now.
[ issue 1269 ] Added test case
Merge branch 'maint-2.4.2'
Renamed Common.Reflect to Common.Reflection
Merge branch 'maint-2.4.2'
[ issue 1269 ] Removed test case using postulates
[ issue 1269 ] Added test case

Case: quote η-reduced and quoteTerm η-reduced
[ issue 1269 ] Added test case

Case: quote η-reduced and non η-reduced
Merge branch 'maint-2.4.2'
[ issue 1269 ] Fixed

We apply TypeChecking.EtaContract.etaContract after the normalisation
in quoteTerm.
[ issue 1269 ] Cosmetic changes to the test cases
[ issue 1269 ] Added test case

Case: quoteTerm η-reduced and non η-reduced
[ issue 1269 ] Added -fwarn-missing-signatures option (and minor changes)
Merge branch 'maint-2.4.2'
[ issue 1269 ] Replaced (>>=) by (<<=)

See https://github.com/agda/agda/commit/65f5cd82a2d5654e944f7ee9b0719539897b8daa#commitcomment-7982607.
Merge branch 'maint-2.4.2'
Merge remote-tracking branch 'upstream/master'