Fix doc/note/assertions.md typo
diff --git a/doc/note/assertions.md b/doc/note/assertions.md
index 00df4ff..7a18197 100644
--- a/doc/note/assertions.md
+++ b/doc/note/assertions.md
@@ -27,7 +27,7 @@
 
 } else {
     x = 1
-	// At this point, "x == 1" is a fact, but "x < 5" is not.
+    // At this point, "x == 1" is a fact, but "x < 5" is not.
 
     // This assertion creates the "x < 5" fact.
     assert x < 5