Add tutorial rooms' capacity in CfP page (#983)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: hypha

src/content/pages/programme/cfp.mdx

@@ -67,6 +67,8 @@ As a community-driven conference, we prioritise sessions that highlight open-sou
 
 #### Planning on submitting a tutorial?
 
+These are interactive, hands-on sessions lasting 180 minutes. Tutorial rooms vary in size, with some accommodating up to 40 participants and others up to 100.
+
 Building on feedback from previous years, this year we’re emphasising tutorials with a strong, hands-on component. In your proposal, please outline how you plan to incorporate active coding sections in your tutorial.
 
 ### 45 minute talks