Fix tables with empty first cell

If the first cell of a table is empty, no entry was created for in in the
markdown table. This resulted in markdown tables which do parse properly.

Author: joouha

html2text/__init__.py

@@ -693,7 +693,7 @@ def link_url(self: HTML2Text, link: str, title: str = "") -> None:
                             self.o("</" + config.TABLE_MARKER_FOR_PAD + ">")
                             self.o("  \n")
                 if tag in ["td", "th"] and start:
-                    if self.split_next_td:
+                    if self.split_next_td or self.table_start:
                         self.o("| ")
                     self.split_next_td = True