Use NA or NULL to remove all table notes.
Table notes are plain text. Huxtable escapes them as required for each output
format.
HTML, LaTeX, Typst and Word output use their native table-footer or table-note
structures. RTF, Markdown and screen output print notes immediately after the
table. Excel writes each note to a merged row below the table. Breakable LaTeX
tables use the threeparttablex package.
Use cell_note() to add notes referenced from individual cells. Referenced
cell notes are printed after unreferenced table notes.
add_footnote() is retained for compatibility only. It adds an ordinary,
full-width row to the table and is soft-deprecated in favour of
add_table_note().