Tried to repair the appstream file

data/io.github.wxmaxima_developers.wxMaxima.appdata.xml

@@ -61,8 +61,7 @@
 	  <li>Many improvements to the manpage and the html documentation</li>
 	  <li>Improved support for pre- and post- super- and subscripts provided 
 	  by Robert Dodier</li>
-	  <li>wxWidget's integrated help browser on some platforms was broken 
-	  => now the default web browser is used</li>
+	  <li>Now the system's web browser is used for showing help</li>
 	  <li>Support for importing static and some types of animated gif files</li>
 	  <li>Animation frames created using draw() now can be popped out 
 	  interactively</li>