Add missing closing ```` for a code block

Fixes formatting bug from #6555 

Signed-off-by: Gera Shegalov <gera@apache.org>

docs/dev/shims.md

@@ -235,6 +235,7 @@ dijkstra -d -p "com.nvidia.spark.rapids.GpuColumnVector (spark3xx-common)" merge
         "org.apache.spark.sql.rapids.GpuFileSourceScanExec (spark330)"  [dist=5.000,
         "com.nvidia.spark.rapids.GpuExec (spark330)"    [dist=3.000,
 ...
+```
 
 RegexReplace could be externalized safely:
 ```
@@ -260,4 +261,4 @@ your class and how it is connected to the rest of the clusters in the definition
 `scc_map`.
 
 This mechanism can also be used as a guidance for refactoring the code in a more self-contained
-packages.
+packages.