docs: Update showcase.md (#1176)

Max

2024-05-29 a99e854d1e932f0d3f1f3e8b59e86f7b99c63086

 quartz/components/renderPage.tsx

@@ -118,11 +118,12 @@
              // skip until we find the blockref that matches
              if (el.properties?.id === blockRef) {
                startIdx = i
                startDepth = Number(el.tagName.substring(1))
                startDepth = depth
              }
            } else if (depth <= startDepth) {
              // looking for new header that is same level or higher
              endIdx = i
              break
            }
          }