Add -Winferred-safe-imports warning

This commit partly reverts e69619e923e84ae61a6bb4357f06862264daa94b
commit by reintroducing Sf_SafeInferred SafeHaskellMode.

We preserve whether module was declared or inferred Safe.  When
declared-Safe module imports inferred-Safe, we warn.  This inferred
status is volatile, often enough it's a happy coincidence, something
which cannot be relied upon. However, explicitly Safe or Trustworthy
packages won't accidentally become Unsafe.

Updates haddock submodule.

1 files changed, 0 insertions, 0 deletions

diff --git a/utils/haddock b/utils/haddock
-Subproject 83bb9870a117f9426e6f6cff6fec3bb6e93a7c1
+Subproject 5e333bad752b9c048ad5400b7159e32f4d3d65b