support tag interpolation in non-root <style> elements (#1147)

[Conduitry]

Fixes #1147 by parsing non-root <style> elements the same way as we parse <textarea> elements.

[codecov-io]

Codecov Report

Merging #1162 into master will increase coverage by 0.27%.
The diff coverage is 62.5%.

@@            Coverage Diff             @@
##           master    #1162      +/-   ##
==========================================
+ Coverage   91.51%   91.78%   +0.27%     
==========================================
  Files         126      126              
  Lines        4526     4627     +101     
  Branches     1462     1507      +45     
==========================================
+ Hits         4142     4247     +105     
- Misses        163      165       +2     
+ Partials      221      215       -6

Impacted Files	Coverage Δ
...nerators/server-side-rendering/visitors/Element.ts	86.48% <0%> (ø)	⬆️
src/generators/nodes/Element.ts	94.44% <0%> (ø)	⬆️
src/parse/state/tag.ts	93.82% <83.33%> (+0.19%)	⬆️
src/css/Stylesheet.ts	94.44% <0%> (+4.44%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0ef8229...8f91648. Read the comment docs.

[Conduitry]

Diff coverage is going to fail until we get #1087 sorted out, which I'm in the process of attempting right now.

[Conduitry]

Still some problems with escaping <, >, & in <style> when we shouldn't. Just going to close this and #1087 and open a new PR to avoid a big git mess.