Try something like the following. (Note: I did not have your emojis so I just used [emoji] where they should go. Substitute the appropriate emojis in their places.)
<%*
let year = await tp.system.prompt('Year',tp.date.now('YYYY'));
let mon = await tp.system.prompt('Month',tp.date.now('M'));
tR += tp.date.now('YYYY MMMM',0,`${year}/${mon}/1`,'YYYY/M/D') + ' Trade Diary [emoji]\n\n';
let curMon = mon;
let day = 0;
while (mon == curMon)
{
let curDay = tp.date.now('dddd, Do MMMM YYYY',day,`${year}/${mon}/1`,'YYYY/M/D');
tR += `## [emoji] ${curDay}\n`;
tR += '### Title\n';
tR += 'Pre Market\n';
tR += ' - \n';
tR += 'Market Hours\n';
tR += ' - \n';
tR += 'Post Market\n';
tR += ' - \n\n';
day++;
curMon = tp.date.now('M',day,`${year}/${mon}/1`,'YYYY/M/D');
}
%>