Update library to require space after $

We cannot easily require a space before $ because some languages, like
C#, strip whitespace from the beginning of the comment text.

shared/util/codeql/util/test/InlineExpectationsTest.qll

@@ -521,7 +521,7 @@ module Make<InlineExpectationsTestSig Impl> {
  * is treated as part of the expected results, except that the comment may contain a `//` sequence
  * to treat the remainder of the line as a regular (non-interpreted) comment.
  */
-private string expectationCommentPattern() { result = "\\s*\\$((?:[^/]|/[^/])*)(?://.*)?" }
+private string expectationCommentPattern() { result = "\\s*\\$ ((?:[^/]|/[^/])*)(?://.*)?" }
 
 /**
  * The possible columns in an expectation comment. The `TDefaultColumn` branch represents the first