qlog: fix markdown in README

diff --git a/tools/qlog/README.md b/tools/qlog/README.md
index 209114d..6da28aa 100644
--- a/tools/qlog/README.md
+++ b/tools/qlog/README.md
@@ -86,7 +86,7 @@
 
 ```rust
 serde_json::to_string_pretty(&trace).unwrap();
-``
+```
 
 which would generate the following:
 
@@ -136,4 +136,4 @@
     ]
   ]
 }
-```
\ No newline at end of file
+```