Add an intro, fix typos

Author: harendra-kumar

getting-started.rst

@@ -1,3 +1,11 @@
+Getting Started with Haskell
+============================
+
+This guide is primarily oriented towards POSIX users with familiarity
+and access to a shell.  On Windows, ``ghc`` is installed on top of
+``msys`` which provides a POSIX shell. This document with some changes may
+apply to Windows as well but it has not been tested.
+
 Install ``ghc`` and ``cabal``
 -----------------------------
 

install/posix-via-shell.rst

@@ -1,9 +1,9 @@
-Install `ghc` and `cabal` on Linux using Shell
+Install `ghc` and `cabal` on POSIX using Shell
 ==============================================
 
-The following example is for Debian 10 For other
+The following example is for Debian 10, for other
 distributions replace the tar file (``.tar.xz``) URL below
-with an appropriate ghc tar image URL `from this page
+with an appropriate ``ghc`` tar image URL `from this page
 <https://www.haskell.org/ghc/download_ghc_8_10_1.html>`_.
 
 Install ``ghc``