Fixes syntax errors and figure 5

[eduperottoni]

• Replaces trust_anchor_id for trust_anchor
• Replaces entity_id for Entity Identifier
• Changes figure 5: constraints claim must be only on Subordinate Statement

[selfissued]

@eduperottoni, please update the PR to add yourself to the acknowledgements.

[selfissued]

@peppelinux, can you update the asciiflow source in line 1021 to match the new diagram contents and put it in the comment thread here so @eduperottoni can add it to the PR? Thanks.

[eduperottoni]

@peppelinux, can you update the asciiflow source in line 1021 to match the new diagram contents and put it in the comment thread here so @eduperottoni can add it to the PR? Thanks.

I've just uploaded the URL of the updated ASCIIFlow image :)