Remove Stability: experimental header from non-internal modules

After so many years, I think it's fair to say that `Data.Text`'s API
is not "experimental" anymore... ;-)

`.Internal` modules however, are not "stable".

Author: hvr

Data/Text.hs

@@ -15,7 +15,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : GHC
 --
 -- A time and space-efficient implementation of Unicode text.

Data/Text/Array.hs

@@ -7,7 +7,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : portable
 --
 -- Packed, unboxed, heap-resident arrays.  Suitable for performance

Data/Text/Encoding.hs

@@ -11,7 +11,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : portable
 --
 -- Functions for converting 'Text' values to and from 'ByteString',

Data/Text/Encoding/Error.hs

@@ -10,7 +10,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : GHC
 --
 -- Types and functions for dealing with encoding and decoding errors

Data/Text/Foreign.hs

@@ -5,7 +5,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : GHC
 --
 -- Support for using 'Text' data with native code via the Haskell

Data/Text/IO.hs

@@ -8,7 +8,6 @@
 --               (c) 2009 Simon Marlow
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : GHC
 --
 -- Efficient locale-sensitive support for text I\/O.

Data/Text/Lazy.hs

@@ -13,7 +13,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : GHC
 --
 -- A time and space-efficient implementation of Unicode text using

Data/Text/Lazy/Builder.hs

@@ -11,7 +11,6 @@
 -- License     : BSD-style (see LICENSE)
 --
 -- Maintainer  : Johan Tibell <[email protected]>
--- Stability   : experimental
 -- Portability : portable to Hugs and GHC
 --
 -- Efficient construction of lazy @Text@ values.  The principal

Data/Text/Lazy/Builder/Int.hs

@@ -9,7 +9,6 @@
 --              (c) 2011 MailRank, Inc.
 -- License:     BSD-style
 -- Maintainer:  Bryan O'Sullivan <[email protected]>
--- Stability:   experimental
 -- Portability: portable
 --
 -- Efficiently write an integral value to a 'Builder'.

Data/Text/Lazy/Encoding.hs

@@ -8,7 +8,6 @@
 --
 -- License     : BSD-style
 -- Maintainer  : [email protected]
--- Stability   : experimental
 -- Portability : portable
 --
 -- Functions for converting lazy 'Text' values to and from lazy