...with the singular exception of intro.js, where it's part of the
package name, not a file extension.
This is mostly to fix an issue where typescript doesn't want you to
import files with a .ts extension (it will accept .js, but that's super
weird if the file doesn't actually have that extension, and when I tried
it it broke the build for Kenton). Changing the import of .js files is
mainly for consistency.
This also changes some imports to use double quotes (") instead of
single quotes ('); I noticed these while searching for import sites to
replace.
Ian Denhardt
ae62d09e37