Fix spelling and remove dead code

Author: smowton

go/ql/src/experimental/CWE-203/Timing.ql

@@ -1,6 +1,6 @@
 /**
- * @name Timing attacks due to comparision of sensitive secrets
- * @description using a non-constant time comparision method to comapre secrets can lead to authoriztion vulnerabilities
+ * @name Timing attacks due to comparison of sensitive secrets
+ * @description using a non-constant time comparison method to comapre secrets can lead to authoriztion vulnerabilities
  * @kind path-problem
  * @problem.severity warning
  * @id go/timing-attack
@@ -19,27 +19,17 @@ private predicate isBadResult(DataFlow::Node e) {
   )
 }
 
-/**
- * A data flow source for timing attack vulnerabilities.
- */
-abstract class Source extends DataFlow::Node { }
-
 /**
  * A data flow sink for timing attack vulnerabilities.
  */
 abstract class Sink extends DataFlow::Node { }
 
-/**
- * A sanitizer for timing attack vulnerabilities.
- */
-abstract class Sanitizer extends DataFlow::Node { }
-
-/** A taint-tracking sink which models comparisions of sensitive variables. */
+/** A taint-tracking sink which models comparisons of sensitive variables. */
 private class SensitiveCompareSink extends Sink {
   ComparisonExpr c;
 
   SensitiveCompareSink() {
-    // We select a comparision where a secret or password is tested.
+    // We select a comparison where a secret or password is tested.
     exists(SensitiveVariableAccess op1, Expr op2 |
       op1.getClassification() = [SensitiveExpr::secret(), SensitiveExpr::password()] and
       // exclude grant to avoid FP from OAuth
@@ -48,10 +38,10 @@ private class SensitiveCompareSink extends Sink {
       op2 = c.getAnOperand() and
       not op1 = op2 and
       not (
-        // Comparisions with `nil` should be excluded.
+        // Comparisons with `nil` should be excluded.
         op2 = Builtin::nil().getAReference()
         or
-        // Comparisions with empty string should also be excluded.
+        // Comparisons with empty string should also be excluded.
         op2.getStringValue().length() = 0
       )
     |