Fix double words and article mismatches in docs.

interface/wx/propgrid/property.h

@@ -1016,7 +1016,7 @@ public:
         @param value
             Int to get the value from.
         @param flags
-            If has ::wxPG_FULL_VALUE, then the value given is a actual value and not an index.
+            If has ::wxPG_FULL_VALUE, then the value given is an actual value and not an index.
 
         @return @true if value was changed.
     */
@@ -2784,7 +2784,7 @@ public:
     void EnsureData();
 
     /**
-        Gets a unsigned number identifying this list.
+        Gets an unsigned number identifying this list.
     */
     wxPGChoicesId GetId() const;