The linter found some issues in viewer.html with </input> which isn't required
and a missing closing div in test/resources/reftest-analyzer.html.
The HTML can now be nicely formatted. In order to not break the build for
mozilla-central, the preprocessor has been fixed in order to take into account
the white spaces at the beginning of a comment line.
And finally, make .prettierrc (which is supposed to be either json or yaml)
itself lintable.
"text/javascript" is not a correct MIME type (the correct one is
"application/javascript") but it's not even needed; all browsers default
to the correct type and treat it as executable JS when type is ommited.
Since not all browsers recognize the "application/javascript" MIME type
the only way to both stay compliant and to support all popular browsers
is to omit the type. It's also shorter this way.
