Docs/updating v1 v2 refs - Covers both #492 and #498 PRs

[TimothyMalahy]

Going to put "Evaluate" to try to clarify which ones might be better to be just moved over to the "https://v1.htmx.org" rather than pointing to v2's readme's. Whatever maintainer's preference.

@carltongibson - Added both your #492 and my #498. I don't contribute a lot to public repos, so let me know if that's a faux pas or anything.

• docs/changelog.rst - Evaluate Pointed to latest version of docs hosted on github. This one should be evaluated if you
• docs/extension_script.rst - Pointed to latest docs, old one 404s. adding "v1." before htmx.org also fixes this, but points to an old version of htmx.
• docs/middleware.rst - Matches PR Fix link to the event-header htmx extension #492 - Should merge cleanly
• example/README.rst - Pointed to latest docs, old one 404s. adding "v1." before htmx.org also fixes this, but points to an old version of htmx.
• example/example/static/htmx.js - Evaluate This is a comment that points to the #extensions header of the docs, which does not 404, but does point to a somewhat irrelevant page. My thought was that both version would be helpful if someone is this in the weeds and the fact it doesn't affect the code. (I think - I'm not a big JS dev)
  • Added in a v1 page that correctly directs to the header reference.
  • Added in the latest version as well underneath
• example/example/templates/_base.html - Evaluate This is another comment that is pointing to docs. I added in v1 and v2 versioning. Used the same logic as static/htmx.js 's commented area - won't impact the code.
• example/example/templates/middleware-tester-table.html - Added in "v1" before the htmx.org domain.

[carltongibson]

@TimothyMalahy Great. Good to combine! Thanks.