Use diff in Code Style Guide, as shown in https://calmcode.io/til/md-diffs.html

Code-Style-Guide.md

@@ -22,19 +22,23 @@ Be reasonable. Keeping within 80 characters is recommended, 120 is the maximum.
 Variables
 ---------
 
-Limit the scope of variables to `local` when within a function.
-
 Wrap your variables in `${curly} ${braces}`.
 
 Use `${snake_case}` for your variable names.
 
 Use existing variables whenever possible:
-* Good: `${PWD}` `${USER}`
-* Bad: `$(pwd)` `$(whoami)`
+```diff
+- print "$(whoami) in $(pwd)"
++ print "${USER} in ${PWD}"
+```
+
+Limit the scope of variables to `local` when within a function.
 
 When declaring a global variable, be explicit and do it using `typeset -g`. This avoids warnings when `WARN_CREATE_GLOBAL` is set:
-* Good: `if (( ! ${+VAR} )) typeset -g VAR=1`
-* Bad: `: ${VAR=1}`
+```diff
+- : ${VAR=1}
++ if (( ! ${+VAR} )) typeset -g VAR=1
+```
 
 Flow logic
 ----------