[otbn,doc] Annotate instructions with the errors they can cause

Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/ip/otbn/util/yaml_to_doc.py b/hw/ip/otbn/util/yaml_to_doc.py
index 1460f6c..6ef8bd3 100755
--- a/hw/ip/otbn/util/yaml_to_doc.py
+++ b/hw/ip/otbn/util/yaml_to_doc.py
@@ -275,9 +275,9 @@
     if insn.errs is not None:
         parts.append(subhead + 'Errors\n')
         if not insn.errs:
-            parts.append('{} cannot cause any synchronous errors.\n'.format(mnem))
+            parts.append('{} cannot cause any software errors.\n'.format(mnem))
         else:
-            parts.append('{} might cause the following synchronous errors:\n'
+            parts.append('{} might cause the following software errors:\n'
                          .format(mnem))
             for desc in insn.errs:
                 parts.append('- {}\n'.format(desc))