Closes #44306 This PR makes two changes: - Uses the new `grid_cols_min_content` API. See more here: https://github.com/zed-industries/zed/pull/44973. - Changes Markdown table rendering to use a single grid instead of creating a new grid per row, so column widths stay consistent across rows. Release Notes: - Fixed an issue where Markdown tables wouldn't render in the hover popover.