Bug fixes

• Fixed issue where frmt_combine couldn't process variable names surrounded by backticks
• Fixed issue where row_grp_plan post space did not respect col_style_plan widths by adding new fill argument to element_block. The fill argument controls whether post space values should be recycled for the cell's data width. For example, a cell width of 3 will be respected by the post space with the following syntax: element_block(post_space = "---", fill = FALSE).
• Remove unused border argument in element_block.
• Fixed bug where row_grp_plan splits on all grouping variables, even if not mentioned. Instead, the logic has been updated to split on those explicitly mentioned, similar to page_plan
• Fixed issue where padding and alignment is lost for non-HTML outputs via the .unicode_ws argument added to print_to_gt() and print_mock_gt(). This defaults to TRUE but should be set to FALSE for RTF outputs (until {gt} bug is resolved).
• Fixed issue where make_mock_data could result in duplicate rows