blobcli: fix README.md code block formatting

Change-Id: I4bc9c0246158eeccfd819089aff095798be1f786
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/383501
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>

examples/blob/cli/README.md

@@ -37,7 +37,7 @@ script lines will simply be skipped, otherwise the tool will exit if
 it runs into an invalid line (ie './blobcli -T test.bs ignore`).
 
 Sample test/bs file:
-~~{.sh}
+~~~{.sh}
 # this is a comment
 -i
 -s bs
@@ -58,4 +58,4 @@ Sample test/bs file:
 -s $B0
 -s $B1
 -s bs
-~~
+~~~