Add notes for 9.2.5

docs/users_guide/9.2.5-notes.rst

+.. _release-9-2-5:
+
+Version 9.2.5
+==============
+
+The significant changes to the various parts of the compiler are listed in the
+following sections.
+
+The :ghc-flag:`LLVM backend <-fllvm>` of this release is to be used with LLVM
+9, 10, 11, or 12.
+
+Compiler
+--------
+
+- Fix a number of issues with the simplifier leading to core lint errors and suboptimal
+  performance (:ghc-ticket:`21694`, :ghc-ticket:`21755`, :ghc-ticket:`22114`).
+
+- Fix a sign extension bug resulting in incorrent runtime results on the native aarch64 backend (:ghc-ticket:`22282`).
+
+- Improve determinism by not inclusing build directories in interface files (:ghc-ticket:`22162`).
+
+- Fix a code generation panic when using SIMD types with unboxed sums (:ghc-ticket:`22187`).
+
+Runtime system
+--------------
+
+-  Fix a bug where attempting to clear the card table of a zero-length
+   array resulted in an integer underflow (:ghc-ticket:`21962`).
+
+Core libraries
+--------------
+
+- Bump ``base`` to 4.16.3.0.
+
+- Bump ``process`` to 1.6.16.0
+
+- base: Fix races in the IOManager to do with the ``setNumCapabilities`` and ``closeFdWith`` functions (:ghc-ticket:`21651`)
+
+
+Included libraries
+------------------
+
+The package database provided with this distribution also contains a number of
+packages other than GHC itself. See the changelogs provided with these packages
+for further change information.
+
+.. ghc-package-list::
+
+    libraries/array/array.cabal:             Dependency of ``ghc`` library
+    libraries/base/base.cabal:               Core library
+    libraries/binary/binary.cabal:           Dependency of ``ghc`` library
+    libraries/bytestring/bytestring.cabal:   Dependency of ``ghc`` library
+    libraries/Cabal/Cabal/Cabal.cabal:       Dependency of ``ghc-pkg`` utility
+    libraries/containers/containers/containers.cabal:   Dependency of ``ghc`` library
+    libraries/deepseq/deepseq.cabal:         Dependency of ``ghc`` library
+    libraries/directory/directory.cabal:     Dependency of ``ghc`` library
+    libraries/exceptions/exceptions.cabal:   Dependency of ``ghc`` and ``haskeline`` library
+    libraries/filepath/filepath.cabal:       Dependency of ``ghc`` library
+    compiler/ghc.cabal:                      The compiler itself
+    libraries/ghci/ghci.cabal:               The REPL interface
+    libraries/ghc-boot/ghc-boot.cabal:       Internal compiler library
+    libraries/ghc-boot-th/ghc-boot-th.cabal: Internal compiler library
+    libraries/ghc-compact/ghc-compact.cabal: Core library
+    libraries/ghc-heap/ghc-heap.cabal:       GHC heap-walking library
+    libraries/ghc-prim/ghc-prim.cabal:       Core library
+    libraries/haskeline/haskeline.cabal:     Dependency of ``ghci`` executable
+    libraries/hpc/hpc.cabal:                 Dependency of ``hpc`` executable
+    libraries/integer-gmp/integer-gmp.cabal: Core library
+    libraries/libiserv/libiserv.cabal:       Internal compiler library
+    libraries/mtl/mtl.cabal:                 Dependency of ``Cabal`` library
+    libraries/parsec/parsec.cabal:           Dependency of ``Cabal`` library
+    libraries/pretty/pretty.cabal:           Dependency of ``ghc`` library
+    libraries/process/process.cabal:         Dependency of ``ghc`` library
+    libraries/stm/stm.cabal:                 Dependency of ``haskeline`` library
+    libraries/template-haskell/template-haskell.cabal:     Core library
+    libraries/terminfo/terminfo.cabal:       Dependency of ``haskeline`` library
+    libraries/text/text.cabal:               Dependency of ``Cabal`` library
+    libraries/time/time.cabal:               Dependency of ``ghc`` library
+    libraries/transformers/transformers.cabal: Dependency of ``ghc`` library
+    libraries/unix/unix.cabal:               Dependency of ``ghc`` library
+    libraries/Win32/Win32.cabal:             Dependency of ``ghc`` library
+    libraries/xhtml/xhtml.cabal:             Dependency of ``haddock`` executable
+
+