==== Goal
Existing Checkuser blocking feature includes some options that are not in the standard //Special:Block// form. We should include them in the //Special:Investigate block// that we are adding in {T248528}.
==== Acceptance criteria
* Under //Additional options// on //Special:Investigate block//, add the following options:
{F31842100, width=350}
** Three options should be in each dropdown: //Prepend//, //Append//, //Replace//
** Default option for User pages should be //Prepend//
** Default option for User talk should be //Append//
** Field should be disabled till the checkbox is clicked
** //Replace talk pages with:// - will replace the users' talk pages with the wikitext supplied in the textarea
** //Replace user pages with:// - will replace the users' user pages with the wikitext supplied in the textarea
** Allow reblocking users per {T249562}