Fix wrong text being used in error message

The code was copied from StagingController in 0496e3a, and I did add the new
text in that commit, I just forgot to adapt the code to actually use it.

Author: stefanhaller

pkg/gui/controllers/commits_files_controller.go

@@ -379,7 +379,7 @@ func (self *CommitFilesController) openDiffTool(node *filetree.CommitFileNode) e
 
 func (self *CommitFilesController) toggleForPatch(selectedNodes []*filetree.CommitFileNode) error {
 	if self.c.AppState.DiffContextSize == 0 {
-		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextToStage,
+		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextForCustomPatch,
 			keybindings.Label(self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView))
 	}
 
@@ -475,7 +475,7 @@ func (self *CommitFilesController) enterCommitFile(node *filetree.CommitFileNode
 	}
 
 	if self.c.AppState.DiffContextSize == 0 {
-		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextToStage,
+		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextForCustomPatch,
 			keybindings.Label(self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView))
 	}