'plugins/ubuntu/ubuntu.plugin.zsh: Solve typos'

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

plugins/ubuntu/ubuntu.plugin.zsh

@@ -69,7 +69,7 @@ alias mydeb='time dpkg-buildpackage -rfakeroot -us -uc'
 # apt-add-repository with automatic install/upgrade of the desired package
 # Usage: aar ppa:xxxxxx/xxxxxx [packagename]
 # If packagename is not given as 2nd argument the function will ask for it and guess the default by taking
-# the part after the / from the ppa name wich is sometimes the right name for the package you want to install
+# the part after the / from the ppa name which is sometimes the right name for the package you want to install
 aar() {
 	if [ -n "$2" ]; then
 		PACKAGE=$2