False positive: `Spellcheck` flags "electron" despite it being in the dictionary

Judging by the first suggestion, this is another bug due to the dictionary case-folding, which is being worked on currently in a draft PR.

Start by reviewing the screenshot and the draft PR referenced in the issue, then trace the dictionary case-folding behavior that handles “electron.” Done means the Spellcheck no longer flags “electron” when it is present in the dictionary, with the result checked against the reported false positive.

Written by the indexing model from the issue text.