Unfortunately, there isn't a specific shortcut mentioned in the provided sources for filling a column with the same text value in a Clay table. However, we do have some options for working with columns that might be helpful:
1. You can duplicate a column by right-clicking on it and selecting "Duplicate".
2. To add a new column, you can hover between two existing columns and click "Add Column".
Is there a particular reason you're looking to fill a column with the same text value? Understanding your goal might help us suggest alternative approaches or features that could be useful for your task.