Use the clearMatches command to clear the highlighting of all matches resulting from a find text operation.
clearMatches
Highlighted occurrences of a find text operation remain highlighted until there is a change to the file contents or until another find text operation is run, even when the cursor is moved (such as by using the mouse or pressing the page-up/page-down keys). This command clears any text highlighted by a find text operation. If no text is highlighted, the command does nothing.
clearMatches