Update Matlab.gitignore (#2533)

Added extensions for prepackaged app and toolbox file, pregenerated helpsearch folders.

Global/Matlab.gitignore

-##---------------------------------------------------
-## Remove autosaves generated by the MATLAB editor
-## We have git for backups!
-##---------------------------------------------------
-
 # Windows default autosave extension
 *.asv
 
@@ -12,12 +7,19 @@
 # Compiled MEX binaries (all platforms)
 *.mex*
 
-# Simulink Code Generation
+# Packaged app and toolbox files 
+*.mlappinstall 
+*.mltbx 
+  
+# Generated helpsearch folders 
+helpsearch*/ 
+
+# Simulink code generation folders
 slprj/
 sccprj/
 
-# Session info
-octave-workspace
-
 # Simulink autosave extension
 *.autosave
+
+# Octave session info
+octave-workspace