trivial: pcmanfm: fix typo in config help

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/pcmanfm/Config.in

@@ -8,8 +8,8 @@ config BR2_PACKAGE_PCMANFM
 	select BR2_PACKAGE_XLIB_LIBX11
 	depends on BR2_PACKAGE_LIBGTK2
 	help
-	  An extremly fast and lightweight file manager which features
-	  tabbed browsing and user-friendly interface.
+	  An extremely fast and lightweight file manager which features
+	  tabbed browsing and a user-friendly interface.
 
 	  http://internap.dl.sourceforge.net/sourceforge/pcmanfm