Use HTML tables for architecture blocks

Every now and then, the following error happens when generating architecture graphs:

Warning: flat edge between adjacent nodes one of which has a record shape - replace records with HTML-like labels
  Edge memory0 -> memory0_in0_mux
Error: lost memory0_in0_mux memory0 edge

It seems like using HTML-based "records" is better. https://graphviz.org/doc/info/shapes.html#html This would also allow printing additional information (like number of cells) on a different row, which in most cases will be better. As well as styling of text etc (bold entity name?).