Skip missing sections

[benasher44]

Changes in this pull request

Ensure we skip sections that become/missing invalid in prefetch calls

Checklist

• [x] All tests pass. Demo project builds and runs.
• [x] I added tests, an experiment, or detailed why my change isn't tested.
• [x] I added an entry to the CHANGELOG.md for any breaking changes, enhancements, or bug fixes.
• [x] I have reviewed the contributing guide

[codecov-commenter]

Codecov Report

Merging #188 into master will decrease coverage by 0.18%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #188      +/-   ##
==========================================
- Coverage   80.57%   80.39%   -0.18%     
==========================================
  Files          33       33              
  Lines        2228     2233       +5     
==========================================
  Hits         1795     1795              
- Misses        433      438       +5     

Impacted Files	Coverage Δ
Sources/Diffing.swift	81.11% <ø> (ø)
Sources/TableCellViewModelDataSource.swift	78.26% <ø> (ø)
Sources/TableViewDriver.swift	77.84% <0.00%> (-2.28%)	:arrow_down: