fix: html() function supports uppercase tags

[erdos]

No description provided.

[codecov]

Codecov Report

Merging #113 (c2768d5) into master (3aefbda) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #113      +/-   ##
==========================================
+ Coverage   93.07%   93.08%   +0.01%     
==========================================
  Files          25       25              
  Lines        1876     1879       +3     
  Branches      106      106              
==========================================
+ Hits         1746     1749       +3     
  Misses         24       24              
  Partials      106      106              

Impacted Files	Coverage Δ
src/stencil/postprocess/html.clj	85.96% <100.00%> (+0.77%)	⬆️

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