docs: fix typo (#397)

absl/container/internal/raw_hash_set.h

@@ -668,7 +668,7 @@ class raw_hash_set {
     }
     }
 
 
     ctrl_t* ctrl_ = nullptr;
     ctrl_t* ctrl_ = nullptr;
-    // To avoid uninitialized member warnigs, put slot_ in an anonymous union.
+    // To avoid uninitialized member warnings, put slot_ in an anonymous union.
     // The member is not initialized on singleton and end iterators.
     // The member is not initialized on singleton and end iterators.
     union {
     union {
       slot_type* slot_;
       slot_type* slot_;