Rework handling of non-root <script> and <style>

[Conduitry]

In practical terms, this fixes hydration of non-root <script> and <style>, and also fixes tag interpolation in non-root <style> (#1147). This supersedes other previous PRs I'd opened.

This switches non-root <script> and <style> back to being parsed as regular elements containing one child Text node (in the case of <script>) and one or more Text or Tag nodes (in the case of <style>). There are also some other changes to make sure we don't escape HTML special characters in DOM or SSR mode for the Text nodes inside non-root <script> and <style> elements.

[codecov-io]

Codecov Report

Merging #1163 into master will increase coverage by 0.19%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1163      +/-   ##
==========================================
+ Coverage   91.51%   91.71%   +0.19%     
==========================================
  Files         126      126              
  Lines        4526     4536      +10     
  Branches     1462     1465       +3     
==========================================
+ Hits         4142     4160      +18     
+ Misses        163      158       -5     
+ Partials      221      218       -3

Impacted Files	Coverage Δ
...nerators/server-side-rendering/visitors/Element.ts	91.42% <ø> (+4.94%)	⬆️
src/parse/state/tag.ts	96.36% <100%> (+2.73%)	⬆️
src/generators/nodes/Element.ts	95.09% <100%> (+0.65%)	⬆️
.../generators/server-side-rendering/visitors/Text.ts	100% <100%> (ø)	⬆️

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[Rich-Harris]

awesome 👍

[Conduitry]

Heh I pushed one more fix to this branch riiiiight after you merged it, so I just went ahead and committed it right to master.

[Rich-Harris]

Cool — looks like I'd already pulled it before I cut the new release