Revert "Update resolve conflict using p instead of k"

Now that we can use 'k' as a menu item binding, use it for the "keep" entry in
the merge menu. I hope this doesn't mess with people's muscle memory, but it's
hopefully not a very frequently used command, and it's simply the better
keybinding.

This reverts commit b32b552.

Author: stefanhaller

pkg/gui/controllers/files_controller.go

@@ -585,7 +585,7 @@ func (self *FilesController) handleNonInlineConflict(file *models.File) error {
 		OnPress: func() error {
 			return handle(self.c.Git().WorkingTree.StageFile, self.c.Tr.Actions.ResolveConflictByKeepingFile)
 		},
-		Key: 'p',
+		Key: 'k',
 	}
 	deleteItem := &types.MenuItem{
 		Label: self.c.Tr.MergeConflictDeleteFile,