Minor fixes for HTML, CSS and JavaScript

[miparnisari]

Fix CSS: space is allowed between ! and important
Fix HTML: space is allowed before and after equal signs for attributes
Fix JS: allows \n as a string

[dblessing]

One simple question, given my lack of JS experience. Otherwise, looks good. Thanks @miparnisari

[dblessing]

I'm no JS expert so forgive me if this is silly. In JS, does the \n come out of the string exactly as is, or is it interpreted as a newline? For example, in Ruby:

# This would output a literal `\n` in the string. Would not be interpreted as a newline
single_str = 'This is a string\n'

# This would output a string with an actual newline.
double_str = "This is a string\n"

If JS treats the \n as Ruby does with single quotes then the ways it's written in this PR is perfect. If JS actually interprets it as a newline as in Ruby with double quotes, then it may be nice to change the token to Str::Escape so it's highlighted differently than surrounding text.

[miparnisari]

Good catch, JS outputs an actual newline in both cases, so it's like Ruby with double quote. I'll fix this later.

[miparnisari]

Fixed!

[dblessing]

Thanks @miparnisari