Show examples of how this works with globs, and warn about POSIX

SC2125.md

@@ -4,7 +4,11 @@
 
 ```sh
 foo={1..9}
-echo $foo
+echo "$foo"
+```
+```sh
+foo="/some/path/*"
+echo "$foo"
 ```
 
 ### Correct code:
@@ -13,6 +17,12 @@ echo $foo
 foo=( {1..9} )
 echo "${foo[@]}"
 ```
+```sh
+foo=(/some/path/*)
+echo "${foo[@]}"
+```
+
+Note that either of these will trigger SC3030 ("In POSIX sh, array references are undefined") if you are using `sh` and not e.g. `bash`.
 
 ### Rationale: