docs: make `Table of contents` as bold
diff --git a/docs/composing-suspending-functions.md b/docs/composing-suspending-functions.md
index ca34fdf..dafa8d6 100644
--- a/docs/composing-suspending-functions.md
+++ b/docs/composing-suspending-functions.md
@@ -16,7 +16,7 @@
 class ComposingGuideTest {
 --> 
 
-## Table of contents
+**Table of contents**
 
 <!--- TOC -->