[MLIR] NFC. Fix doc comment for AliasResult::isNo

[bondhugula]

Summary

Fix doc comment for AliasResult::isNo. NFC.

mlir/include/mlir/Analysis/AliasAnalysis.h

public:
 
   /// Merge this alias result with `other` and return a new result that
   /// represents the conservative merge of both results. If the results
   /// represent a known alias, the stronger alias is chosen (i.e.
   /// Partial+Must=Must). If the two results are conflicting, MayAlias is
   /// returned.
   AliasResult merge(AliasResult other) const;
 
-  /// Returns if this result is a partial alias.
+  /// Returns if this result indicates no possibility of aliasing.
   bool isNo() const { return kind == NoAlias; }
 
   /// Returns if this result is a may alias.
   bool isMay() const { return kind == MayAlias; }
 
   /// Returns if this result is a must alias.
   bool isMust() const { return kind == MustAlias; }