docs: Apply Jim's suggestions

Co-authored-by: Jim Galasyn <[email protected]>

docs/developer-guide/variable-substitution.md

@@ -89,12 +89,12 @@ ksqlDB doesn't add single-quotes to values during variable substitution. Also, y
 Escape substitution variables
 -----------------------------
 
-If you want to escape a variable reference, so it is not substituted, then use double `$$` characters.
+To escape a variable reference, so it isn't substituted, use double dollar-sign characters, `$$`. The following example shows how to escape a variable named `format`.
 ```
 DEFINE format = 'AVRO';
 SELECT '$${format}' FROM stream;
 ```
-The above query will become `SELECT '${format}' FROM stream`
+ksqlDB converts the previous query to `SELECT '${format}' FROM stream`.
 
 Context for substitution variables
 ----------------------------------