HTML fixes

[NoseyNick]

For #187 - a big bunch of HTML fixes in order to get valid HTML / clean results from https://validator.w3.org/nu/?doc=https%3A%2F%2Fartemis-nerds.github.io%2Fprotocol-docs%2F Specifically:

• <content> is apparently no longer a thing? Really? Converted to <div>
• The above required a corresponding script.js fix too
• <a target="_new"> should apparently now be <a target="_blank">
• Some <ul> moved outside <p>
• Some <dl> / <dt> / <dd> structure fixed
• Unfortunately A LOT of indentation fixed because of the above - see diffs without whitespace
• This may cause merge conflicts with some of my other pending changes - will fix case-by-case
• Apparently bad practice to change number of cols in a table? Added some empty <td>
• Fixed the toggleredalert duplicate to the correct toggleshields - obsoletes #182 / fixes #181
• alt added to all <img>

[NoseyNick]

Would much appreciate a review from @rjwut , for this PR and/or the others?

[NoseyNick]

Conflicts. As expected. Will resolve and merge. Thanks @rjwut !

[NoseyNick]

https://validator.w3.org/nu/?doc=https%3A%2F%2Fartemis-nerds.github.io%2Fprotocol-docs%2F is now clean :grin:

https://validator.w3.org/unicorn/check?ucn_uri=https%3A%2F%2Fartemis-nerds.github.io%2Fprotocol-docs%2F&ucn_task=conformance# still has some errors, but they're all in bootstrap and I'm not sure we can be held responsible for those. Bootstrap 4.4.1 looks to be just as bad if not worse :laughing: