Don't inherit caret colour from code-input elements into plugin dialog

[WebCoder49]

For a dark-theme code-input this causes bad contrast on the light-theme dialogs for FindAndReplace and GoToLine.

Add this to the input element's CSS in each plugin:

caretColor: currentColor; /* Don't inherit from the code-input element. */

[WebCoder49]

For the reference, this is what was fixed; the text colour of the code-input element (here white) was inherited to the find and replace dialog: