metainfo: Fix email, add developer_name tag, extend first line of description

Author: rpavlik

res/freedesktop/com.solvespace.SolveSpace.metainfo.xml.in

@@ -8,6 +8,7 @@
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>GPL-3.0-or-later</project_license>
   <update_contact>rylie_AT_ryliepavlik.com</update_contact>
+  <developer_name>The SolveSpace Community, originally by Jonathan Westhues and other authors</developer_name>
 
   <categories>
     <category>Graphics</category>
@@ -16,7 +17,7 @@
   </categories>
   <description>
     <p>
-      SolveSpace is a free (GPLv3) parametric 3d CAD tool. Applications include:
+      SolveSpace is a free (GPLv3) parametric 2d/3d CAD (computer-aided design) tool. Applications include:
     </p>
     <ul>
       <li>Modeling 3d parts — draw with extrudes, revolves/helix, and Boolean operations</li>