Following the issue #23380 and PR #25038, this commit changes all
occurences of `uri` into `url` in all comments, local variables,
handlebars templates (.hbs) function names and their callers in
all `.js` and `.ts` files.
Since we are migrating from JavaScript to TypeScript
some files in the documentation are still with their
old extension. This commit changes those file extensions.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>