fix: pressing space too early with the dark note theme doesnt highlight the word as incorrect (mokshsinghji)

[mokshsinghji]

Description

A new style is added to change the colour of characters that were missed while doing a typing test.

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Closes #5042

[Miodec]

I would color the missed characters red to compensate for the missing underline.

EDIT: hmm but then it wil look like these characters were typed..

[Miodec]

Nevermind, it looks fine