Revert "third_party/protobuf: Update to HEAD (83d681ee2c)"

third_party/protobuf/objectivec/GPBUnknownFieldSet.h

Index: third_party/protobuf/objectivec/GPBUnknownFieldSet.h
diff --git a/third_party/protobuf/objectivec/GPBUnknownFieldSet.h b/third_party/protobuf/objectivec/GPBUnknownFieldSet.h
index 1b5f24f392d180e61ac06e9d9632fd99430a43b6..cf612993d4bb6091d2cfe04e0de5035f7f45e215 100644
--- a/third_party/protobuf/objectivec/GPBUnknownFieldSet.h
+++ b/third_party/protobuf/objectivec/GPBUnknownFieldSet.h
@@ -34,48 +34,31 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-/**
- * A collection of unknown fields. Fields parsed from the binary representation
- * of a message that are unknown end up in an instance of this set. This only
- * applies for files declared with the "proto2" syntax. Files declared with the
- * "proto3" syntax discard the unknown values.
- **/
+/// A collection of unknown fields.
 @interface GPBUnknownFieldSet : NSObject<NSCopying>
 
-/**
- * Tests to see if the given field number has a value.
- *
- * @param number The field number to check.
- *
- * @return YES if there is an unknown field for the given field number.
- **/
+/// Tests to see if the given field number has a value.
+///
+/// @param number The field number to check.
+///
+/// @return YES if there is an unknown field for the given field number.
 - (BOOL)hasField:(int32_t)number;
 
-/**
- * Fetches the GPBUnknownField for the given field number.
- *
- * @param number The field number to look up.
- *
- * @return The GPBUnknownField or nil if none found.
- **/
+/// Fetches the @c GPBUnknownField for the given field number.
+///
+/// @param number The field number to look up.
+///
+/// @return The @c GPBUnknownField or nil.
 - (nullable GPBUnknownField *)getField:(int32_t)number;
 
-/**
- * @return The number of fields in this set.
- **/
+/// Returns the number of fields in this set.
 - (NSUInteger)countOfFields;
 
-/**
- * Adds the given field to the set.
- *
- * @param field The field to add to the set.
- **/
+/// Adds the given field to the set.
 - (void)addField:(GPBUnknownField *)field;
 
-/**
- * @return An array of the GPBUnknownFields sorted by the field numbers.
- **/
-- (NSArray<GPBUnknownField *> *)sortedFields;
+/// Returns an NSArray of the @c GPBUnknownFields sorted by the field numbers.
+- (NSArray<GPBUnknownField*> *)sortedFields;
 
 @end