Configuration that details how spell check should be performed.
Specifies the SpellCheckService used to spell check text input and the TextStyle used to style text with misspelled words.
If the SpellCheckService is left null, spell check is disabled by default unless the DefaultSpellCheckService is supported, in which case it is used. It is currently supported only on Android and iOS.
If this configuration is left null, then spell check is disabled by default.
final SpellCheckConfiguration? spellCheckConfiguration;