[Gardening] Clarified documentation.

Author: nate-chandler

include/swift/SIL/MemAccessUtils.h

@@ -887,10 +887,10 @@ namespace swift {
 /// For convenience, encapsulate and AccessStorage value along with its
 /// accessed base address.
 struct AccessStorageWithBase {
-  /// Identical to AccessStorage::compute but preserves the access base.
+  /// Identical to AccessStorage::computeInScope but walks through begin_access.
   static AccessStorageWithBase compute(SILValue sourceAddress);
 
-  /// Identical to AccessStorage::computeInScope but preserves the base.
+  /// Identical to AccessStorage::compute but stops at begin_access
   static AccessStorageWithBase computeInScope(SILValue sourceAddress);
 
   AccessStorage storage;