move getACommonTld to the shared pack

python/ql/lib/semmle/python/dataflow/new/Regexp.qll

@@ -9,11 +9,12 @@ private import semmle.python.dataflow.new.DataFlow
 /**
  * Provides utility predicates related to regular expressions.
  */
-module RegExpPatterns {
+deprecated module RegExpPatterns {
   /**
    * Gets a pattern that matches common top-level domain names in lower case.
+   * DEPRECATED: use the similarly named predicate from `HostnameRegex` from the `regex` pack instead.
    */
-  string getACommonTld() {
+  deprecated string getACommonTld() {
     // according to ranking by http://google.com/search?q=site:.<<TLD>>
     result = "(?:com|org|edu|gov|uk|net|io)(?![a-z0-9])"
   }

python/ql/lib/semmle/python/security/regexp/HostnameRegex.qll

@@ -13,8 +13,6 @@ private module Impl implements Shared::HostnameRegexpSig<TreeImpl> {
   class DataFlowNode = DataFlow::Node;
 
   class RegExpPatternSource = Regexp::RegExpPatternSource;
-
-  string getACommonTld() { result = Regexp::RegExpPatterns::getACommonTld() }
 }
 
 import Shared::Make<TreeImpl, Impl>