From Ved's feedback on the PR.

Based on feedback from Ved.

This will make space for Sddbltrp, and possibly other extensions that
need more causes.

Fix Action encoding table column width.

fixed missing hartsel reference when determining HARTSELLEN

Asciidoc conversion fixes for Sdext

Asciidoc conversion fixes for appendix A

Autowidth led to the first column to be so narrow that "Value" was
taking up two rows.

Fix various issues with hyperlinks within the document.

Fixes reference to JTAG register table.

Because asciidoc doesn't support links inside literal blocks.

Minor fixes to table layout.

Still doesn't look quite right, but right aligning makes no sense for a
range.

Fixes alignment of the field name within the tables, as pointed out in

Sometimes they would wrap "Write", as pointed out in #993.

Fix tdata1 having duplicate register diagrams

Fixes a duplicate diagram for tdata1, reported in #989.

Fix asciidoc conversion for DXLEN definition.

Fix minor AsciiDoc conversion problem.

Dual-license XML files BSD-2-Clause and CC-BY-4.0

Ensure a newline at the end of registers description

Without this, the `[cols=...]` line would show up in the rendered text
(at the start of section 4.10).

The rule makes those targets from scratch now.

Fix `hartset` -> {hartsel}

Fixes #972