Updated SC2051 (markdown)

SC2051.md

@@ -2,17 +2,21 @@
 
 ### Problematic code:
 
+```bash
 for i in {1..$n}
 do
   echo "$i"
 done
+```
 
 ### Correct code:
 
+```bash
 for ((i=0; i<n; i++))
 do
   echo "$i"
 done
+```
 
 ### Rationale:
 
@@ -34,4 +38,4 @@ done <  <(eval "printf '%s\0' $(printf "{%q..%q}.jpg" "$from" "$to")")
 
 ### Exceptions
 
-None (if you're writing for e.g. zsh, make sure the shebang indicates this so shellcheck won't warn)
+None (if you're writing for e.g. zsh, make sure the shebang indicates this so shellcheck won't warn)