Add Haddock `/Since: 4.4.0.0/` comments to symbols

This commit retroactively adds `/Since: 4.4.0.0/` annotations to symbols
newly added/exposed in `base-4.4.0.0` (as shipped with GHC 7.2.1).

See also 6368362f which adds the respective annotation for symbols newly
added in `base-4.7.0.0` (that goes together with GHC 7.8.1).

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Remove obsolete pre-Haddock-2 `#hide` pragmas

The now obsolete (and redundant) `#hide` pragmas have been superseded by
`{-# OPTIONS_HADDOCK hide #-}` pragmas which are used by most of the
affected modules anyway.

This commit also adds proper `{-# OPTIONS_HADDOCK hide #-}` pragmas to
`GHC.Desugar` and `GHC.IO.Encoding.Iconv` which had only the ineffective
`#hide` annotation.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>