Address review comments

Co-Authored-By: Maryam Ziyad <maryamziyadm@gmail.com>

examples/string-templates/string_templates.bal

@@ -5,14 +5,10 @@ public function main() {
     string s1 = string `line one \n rest of line 1 ${"\n"} second line`;
     io:println(s1);
 
-    // Use interpolations to add ` and  $ characters.
+    // Use interpolations to add the ` and  $ characters.
     string s2 = string `Backtick: ${"`"} Dollar: ${"$"}`;
     io:println(s2);
 
-    // Template expressions can be nested.
-    string s3 = string `outer ${string `inner ${5} inner rest`} rest`;
-    io:println(s3);
-
     // You can use an empty string interpolation to break a template expression
     // across multiple lines.
     string s4 = string `prefix ${