Add highlighting to code-blocks

SC1020.md

@@ -2,13 +2,13 @@
 
 ### Problematic code:
 
-```
+```sh
 if [ "$STUFF" = ""]; then
 ```
 
 ### Correct code:
 
-```
+```sh
 if [ "$STUFF" = "" ]; then
 ```
 
@@ -16,11 +16,10 @@ if [ "$STUFF" = "" ]; then
 Bourne shells are very whitespace sensitive. Adding or removing spaces can drastically alter the meaning of a script. In these cases, ShellCheck has noticed that you're missing a space at the position indicated.
 
 ### Exceptions
-none.
+None.
 
 ### Ignore
-```
+```sh
 # shellcheck disable=SC1020
 if [ "$STUFF" = ""]; then
-...
-```
+```