Fix: handle nested hydration better

[eight04]

Fixes #244

With this PR, you can nest hydrate-client={props} directive. Elderjs converts them into {...props} automatically if hydration is not applicable.

[codecov-commenter]

Codecov Report

Merging #258 (77e4d5c) into master (6d2cd15) will increase coverage by 0.10%.
The diff coverage is 94.73%.

@@            Coverage Diff             @@
##           master     #258      +/-   ##
==========================================
+ Coverage   81.30%   81.40%   +0.10%     
==========================================
  Files          47       47              
  Lines        2054     2060       +6     
  Branches      463      466       +3     
==========================================
+ Hits         1670     1677       +7     
+ Misses        382      381       -1     
  Partials        2        2              

Impacted Files	Coverage Δ
src/rollup/rollupPlugin.ts	75.20% <75.00%> (+0.09%)	⬆️
src/partialHydration/inlineSvelteComponent.ts	100.00% <100.00%> (ø)
src/partialHydration/mountComponentsInHtml.ts	88.23% <100.00%> (+4.02%)	⬆️
src/partialHydration/partialHydration.ts	100.00% <100.00%> (ø)
src/utils/Page.ts	88.18% <100.00%> (ø)
src/utils/svelteComponent.ts	93.93% <100.00%> (+0.18%)	⬆️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more