Explain tab-delimited tables a bit better

doc/bugs/Tab_delimited_tables_don__39__t_work.mdwn

@@ -18,3 +18,5 @@ alpha	beta
 """]]
 >
 > So, I think this can be considered [[not_a_bug|done]]? --[[smcv]]
+
+>> I've clarified the documentation. --[[smcv]]

doc/ikiwiki/directive/table.mdwn

@@ -42,4 +42,9 @@ cells. For example:
   as the table header. Set it to "no" to make a table without a header, or
   "column" to make the first column be the header.
 
+For tab-delimited tables (often obtained by copying and pasting from HTML
+or a spreadsheet), `delimiter` must be set to a literal tab character. These
+are difficult to type in most web browsers - copying and pasting one from
+the table data is likely to be the easiest way.
+
 [[!meta robots="noindex, follow"]]