Fix range select bug

After discarding file changes from the commit, the was still referencing
these indexes as being part of the range select. The consequence was
needing to hit escape twice to exit commit files in some situations.
Canceling the range select after discarding changes fixes that.

pkg/gui/controllers/commits_files_controller.go

@@ -217,7 +217,10 @@ func (self *CommitFilesController) discard(selectedNodes []*filetree.CommitFileN
 					return err
 				}
 
-				return self.c.Refresh(types.RefreshOptions{Mode: types.BLOCK_UI})
+				if self.context().RangeSelectEnabled() {
+					self.context().GetList().CancelRangeSelect()
+				}
+				return self.c.Refresh(types.RefreshOptions{Mode: types.SYNC})
 			})
 		},
 	})