basic fix for broken function preview

[bomsy]

Associated Issue

This fixes the broken function preview, a possible regression.

Before

After

Summary of Changes

• change div to span
• use item instead of item.contents.value to get the function details for preview
• If parameterNames does not exist the UI breaks

[codecov]

Codecov Report

Merging #2613 into master will decrease coverage by 0.48%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2613      +/-   ##
==========================================
- Coverage   59.03%   58.55%   -0.49%     
==========================================
  Files          51       51              
  Lines        1943     1959      +16     
  Branches      398      398              
==========================================
  Hits         1147     1147              
- Misses        796      812      +16

Impacted Files	Coverage Δ
src/utils/editor/index.js	15.38% <0%> (-5.03%)	⬇️

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