ensure charset set to utf8 on all pages

[natestemen]

When using the recommended way to develop this site (python -m http.server 8000 --bind 127.0.0.1), many unicode characters are not displayed properly. Thankfully this does not effect production, but this changes ensures further consistency between prod and dev.

before	after

Note: In some files <meta charset="UTF-8"> is added while in others it's <meta charset="UTF-8" />. This discrepancy comes from the fact that prettier is only run on HTML files in the root directory (and it likes the self closing syntax), and not within any directory.

[nathanshammah]

Great find @natestemen.

[natestemen]

I've figured out what is the reason for the difference in prod and dev.

On dev the site is served by python as is and has a rather limited set of HTTP headers that it sends along with requests:

Server: SimpleHTTP/0.6 Python/3.10.6
Date: Tue, 23 Aug 2022 18:04:19 GMT
Content-type: text/html
Content-Length: 18438
Last-Modified: Mon, 22 Aug 2022 20:37:02 GMT

As you can see the Content-type is only text/html.

On prod where GitHub is in control of the server, there is a larger set of headers added to requests, and in particular a change to the Content-type:

server: GitHub.com
content-type: text/html; charset=utf-8
last-modified: Tue, 23 Aug 2022 14:57:01 GMT
access-control-allow-origin: *
etag: W/"6304eabd-481e"
expires: Tue, 23 Aug 2022 18:09:01 GMT
cache-control: max-age=600
content-encoding: gzip
x-proxy-cache: MISS
x-github-request-id: BB30:6933:208829:25B19F:63051565
accept-ranges: bytes
date: Tue, 23 Aug 2022 18:05:05 GMT
via: 1.1 varnish
age: 6
x-served-by: cache-bfi-krnt7300089-BFI
x-cache: HIT
x-cache-hits: 1
x-timer: S1661277905.024509,VS0,VE1
vary: Accept-Encoding
x-fastly-request-id: 31c8c7e400e77e63d4223da65e6c412521d5c574
content-length: 5259
X-Firefox-Spdy: h2

[nathanshammah]

Maybe @WrathfulSpatula you have the skills to review this PR? Otherwise I am happy to merge on good faith basis.

[WrathfulSpatula]

@natestemen At high level, the self-closing tags are probably "correct." A browser might understand it either way, but, as a web developer, my intuition is that every opening tag in the DOM should have a closing tag. I'm still reviewing, but you might want to go in manually and make them all self-closing, if that's reasonable.

[natestemen]

After conversing with Dan, we decided to not use the "formally correct" self-closing tags in all files since a linter/formatter is not being applied across all files. If we transition to that, these will be updated.