Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/objectivec/GPBExtensionRegistry.h

Index: third_party/protobuf/objectivec/GPBExtensionRegistry.h
diff --git a/third_party/protobuf/objectivec/GPBExtensionRegistry.h b/third_party/protobuf/objectivec/GPBExtensionRegistry.h
index d79632d28b079ecc31c8b27e99179ca23f274888..08a6472ac0748c3f8a31a67a7ccc74c4e0b36a58 100644
--- a/third_party/protobuf/objectivec/GPBExtensionRegistry.h
+++ b/third_party/protobuf/objectivec/GPBExtensionRegistry.h
@@ -35,50 +35,45 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-/**
- * A table of known extensions, searchable by name or field number.  When
- * parsing a protocol message that might have extensions, you must provide a
- * GPBExtensionRegistry in which you have registered any extensions that you
- * want to be able to parse. Otherwise, those extensions will just be treated
- * like unknown fields.
- *
- * The *Root classes provide `+extensionRegistry` for the extensions defined
- * in a given file *and* all files it imports. You can also create a
- * GPBExtensionRegistry, and merge those registries to handle parsing
- * extensions defined from non overlapping files.
- *
- * ```
- * GPBExtensionRegistry *registry = [[MyProtoFileRoot extensionRegistry] copy];
- * [registry addExtension:[OtherMessage neededExtension]]; // Not in MyProtoFile
- * NSError *parseError;
- * MyMessage *msg = [MyMessage parseData:data extensionRegistry:registry error:&parseError];
- * ```
- **/
+/// A table of known extensions, searchable by name or field number.  When
+/// parsing a protocol message that might have extensions, you must provide a
+/// @c GPBExtensionRegistry in which you have registered any extensions that you
+/// want to be able to parse. Otherwise, those extensions will just be treated
+/// like unknown fields.
+///
+/// The @c *Root classes provide @c +extensionRegistry for the extensions defined
+/// in a given file *and* all files it imports. You can also create a
+/// @c GPBExtensionRegistry, and merge those registries to handle parsing
+/// extensions defined from non overlapping files.
+///
+/// @code
+/// GPBExtensionRegistry *registry =
+///     [[[MyProtoFileRoot extensionRegistry] copy] autorelease];
+/// [registry addExtension:[OtherMessage neededExtension];  // Not in MyProtoFile
+/// NSError *parseError = nil;
+/// MyMessage *msg = [MyMessage parseData:data
+///                     extensionRegistry:registry
+///                                 error:&parseError];
+/// @endcode
 @interface GPBExtensionRegistry : NSObject<NSCopying>
 
-/**
- * Adds the given GPBExtensionDescriptor to this registry.
- *
- * @param extension The extension description to add.
- **/
+/// Add the given @c GPBExtensionDescriptor to this registry.
+///
+/// @param extension The extension description to add.
 - (void)addExtension:(GPBExtensionDescriptor *)extension;
 
-/**
- * Adds all the extensions from another registry to this registry.
- *
- * @param registry The registry to merge into this registry.
- **/
+/// Adds all the extensions from another registry to this registry.
+///
+/// @param registry The registry to merge into this registry.
 - (void)addExtensions:(GPBExtensionRegistry *)registry;
 
-/**
- * Looks for the extension registered for the given field number on a given
- * GPBDescriptor.
- *
- * @param descriptor  The descriptor to look for a registered extension on.
- * @param fieldNumber The field number of the extension to look for.
- *
- * @return The registered GPBExtensionDescriptor or nil if none was found.
- **/
+/// Looks for the extension registered for the given field number on a given
+/// @c GPBDescriptor.
+///
+/// @param descriptor  The descriptor to look for a registered extension on.
+/// @param fieldNumber The field number of an extension to look for.
+///
+/// @return The registered @c GPBExtensionDescripto or nil if none was found.
 - (nullable GPBExtensionDescriptor *)extensionForDescriptor:(GPBDescriptor *)descriptor
                                                 fieldNumber:(NSInteger)fieldNumber;