fix typo in README

README.html

@@ -31,7 +31,7 @@
 <p>*Current UxPlay is also a pull request on the original site https://github.com/antimof/UxPlay ; that original project is inactive, but the pull requests are now being periodically merged with the antimof tree (thank you antimof!).</p>
 <h2 id="building-uxplay-on-linux-or-bsd">Building UxPlay on Linux (or *BSD):</h2>
 <p>(Instructions for Debian/Ubuntu; adapt these for other Linuxes; for macOS, see below). See <a href="#troubleshooting">Troubleshooting</a> below for help with any difficulties.</p>
-<p>You need a C/C++ compiler (e.g. g++) with the standard development libraries installed. Debian-based systems provide a package “build-essential” for use in compiling software. You also need pkg-config: if it is is not found by “<code>which pkg-config</code>”, install pkg-config or its work-alike replacement pkgconf. Also make sure that cmake&gt;=3.4.1 is installed: “<code>sudo apt-get install cmake</code>” (add <code>build-essential</code> and <code>pkg-config</code> (or <code>pkgconf</code>) to this if needed).</p>
+<p>You need a C/C++ compiler (e.g. g++) with the standard development libraries installed. Debian-based systems provide a package “build-essential” for use in compiling software. You also need pkg-config: if it is not found by “<code>which pkg-config</code>”, install pkg-config or its work-alike replacement pkgconf. Also make sure that cmake&gt;=3.4.1 is installed: “<code>sudo apt-get install cmake</code>” (add <code>build-essential</code> and <code>pkg-config</code> (or <code>pkgconf</code>) to this if needed).</p>
 <p>Make sure that your distribution provides OpenSSL 1.1.1 or later, and libplist 2.0 or later. (This means Debian 10 “Buster”, Ubuntu 18.04 or later.) If it does not, you may need to build and install these from source (see below).</p>
 <p>In a terminal window, change directories to the source directory of the downloaded source code (“UxPlay-*”, “*” = “master” or the release tag for zipfile downloads, “UxPlay” for “git clone” downloads), then follow the instructions below:</p>
 <p><strong>Note:</strong> By default UxPlay will be built with optimization for the computer it is built on; when this is not the case, as when you are packaging for a distribution, use the cmake option <code>-DNO_MARCH_NATIVE=ON</code>.</p>

README.md

@@ -129,7 +129,8 @@ now being periodically merged with the antimof tree (thank you antimof!).
 See [Troubleshooting](#troubleshooting) below for help with any difficulties.
 
 You need a C/C++ compiler (e.g. g++) with the standard development libraries installed.  Debian-based
-systems provide a package "build-essential" for use in compiling software.   You also need pkg-config: if it is is not found by "`which pkg-config`",
+systems provide a package "build-essential" for use in compiling software.   You also need pkg-config: if it is
+not found by "`which pkg-config`",
 install pkg-config or its  work-alike replacement pkgconf.   Also make sure that cmake>=3.4.1
 is installed: "`sudo apt-get install cmake`" (add ``build-essential`` and
 `pkg-config` (or ``pkgconf``)  to this if needed).

README.txt

@@ -169,7 +169,7 @@ help with any difficulties.
 You need a C/C++ compiler (e.g. g++) with the standard development
 libraries installed. Debian-based systems provide a package
 "build-essential" for use in compiling software. You also need
-pkg-config: if it is is not found by "`which pkg-config`", install
+pkg-config: if it is not found by "`which pkg-config`", install
 pkg-config or its work-alike replacement pkgconf. Also make sure that
 cmake\>=3.4.1 is installed: "`sudo apt-get install cmake`" (add
 `build-essential` and `pkg-config` (or `pkgconf`) to this if needed).