message: README: fix typos and grammar
diff: This program is a simple translations editor for PO and XLIFF files. It also
  serves as a GUI frontend to more GNU gettext utilities (win32 version
  is part of the distribution) and catalogs editor/source code parser. It helps
  -with translating application into another language. For details on principles
  +with translating applications into another language. For details on principles
  of the solution used, see GNU gettext documentation or wxWidgets' wxLocale
  class reference.
  @@ -20,8 +20,8 @@ class reference.
  Installing
  ============
  -Easily-installable prebuilt binaries are provided for Windows and macOS and
  -available from https://poedit.net/download.
  +Easily-installable prebuilt binaries for Windows and macOS are available from
  +https://poedit.net/download.
  Official binaries for Linux are available as a Snap at https://snapcraft.io/poedit
  Most Linux distributions also include native Poedit packages.
  @@ -53,8 +53,8 @@ Do the usual thing:
  make
  make install
  -You must have the dependencies installed in a location configure will find,
  -e.g. by setting CPPFLAGS and LDFLAGS appropriately.
  +You must have the dependencies installed in a location where configure will find
  +them, e.g. by setting CPPFLAGS and LDFLAGS appropriately.
  macOS
  @@ -85,12 +85,12 @@ project.
  Installing from Git repository
  --------------------------------
  -Get the sources from github (https://github.com/vslavik/poedit):
  +Get the sources from GitHub (https://github.com/vslavik/poedit):
  git clone https://github.com/vslavik/poedit.git
  If you are on Windows or OSX, you'll need all the dependencies too. After
  -closing, run the following command:
  +cloning the repository, run the following command:
  git submodule update --init --recursive
  @@ -119,12 +119,12 @@ Poedit is released under the MIT license and you're free to do
  whatever you want with it and its source code (well, almost :-) -- see the
  license text).
  -See the COPYING file for details on program's licensing and the
  +See the COPYING file for details on the program's licensing and the
  icons/README file for details on the icons.
  Windows and macOS versions contain GNU gettext binaries. They are distributed
  under the GNU General Public License and their source code is available from
  -http://www.gnu.org/software/gettext or, if you have difficulties getting them
  +http://www.gnu.org/software/gettext. If you have difficulties getting them
  from there, email me for a copy of the sources.
  