doc: make the heading consistent

All the other headings are in level 3. This patch fixes the offending
heading to use level 3.

PR-URL: nodejs#11569

Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/deprecations.md

@@ -38,3 +38,79 @@ Type: Runtime
 `--debug` activates the legacy V8 debugger interface, which has been removed as
 of V8 5.8. It is replaced by Inspector which is activated with `--inspect`
 instead.
+
+<a id="DEP0063"></a>
+### DEP0063: ServerResponse.prototype.writeHeader()
+
+Type: Documentation-only
+
+The `http` module `ServerResponse.prototype.writeHeader()` API has been
+deprecated. Please use `ServerResponse.prototype.writeHead()` instead.
+
+*Note*: The `ServerResponse.prototype.writeHeader()` method was never documented
+as an officially supported API.
+
+[alloc]: buffer.html#buffer_class_method_buffer_alloc_size_fill_encoding
+[alloc_unsafe_size]: buffer.html#buffer_class_method_buffer_allocunsafe_size
+[`Buffer.allocUnsafeSlow(size)`]: buffer.html#buffer_class_method_buffer_allocunsafeslow_size
+[`Buffer.isBuffer()`]: buffer.html#buffer_class_method_buffer_isbuffer_obj
+[`Buffer.from(array)`]: buffer.html#buffer_class_method_buffer_from_array
+[from_arraybuffer]: buffer.html#buffer_class_method_buffer_from_arraybuffer_byteoffset_length
+[`Buffer.from(buffer)`]: buffer.html#buffer_class_method_buffer_from_buffer
+[from_string_encoding]: buffer.html#buffer_class_method_buffer_from_string_encoding
+[`SlowBuffer`]: buffer.html#buffer_class_slowbuffer
+[`child_process`]: child_process.html
+[`console.error()`]: console.html#console_console_error_data_args
+[`console.log()`]: console.html#console_console_log_data_args
+[`crypto.createCredentials()`]: crypto.html#crypto_crypto_createcredentials_details
+[`crypto.pbkdf2()`]: crypto.html#crypto_crypto_pbkdf2_password_salt_iterations_keylen_digest_callback
+[`domain`]: domain.html
+[`Domain.dispose()`]: domain.html#domain_domain_dispose
+[`ecdh.setPublicKey()`]: crypto.html#crypto_ecdh_setpublickey_public_key_encoding
+[`emitter.listenerCount(eventName)`]: events.html#events_emitter_listenercount_eventname
+[`EventEmitter.listenerCount(emitter, eventName)`]: events.html#events_eventemitter_listenercount_emitter_eventname
+[`fs.exists(path, callback)`]: fs.html#fs_fs_exists_path_callback
+[`fs.stat()`]: fs.html#fs_fs_stat_path_callback
+[`fs.access()`]: fs.html#fs_fs_access_path_mode_callback
+[`fs.lchmod(path, mode, callback)`]: fs.html#fs_fs_lchmod_path_mode_callback
+[`fs.lchmodSync(path, mode)`]: fs.html#fs_fs_lchmodsync_path_mode
+[`fs.lchown(path, uid, gid, callback)`]: fs.html#fs_fs_lchown_path_uid_gid_callback
+[`fs.lchownSync(path, uid, gid)`]: fs.html#fs_fs_lchownsync_path_uid_gid
+[`fs.read()`]: fs.html#fs_fs_read_fd_buffer_offset_length_position_callback
+[`fs.readSync()`]: fs.html#fs_fs_readsync_fd_buffer_offset_length_position
+[`Server.connections`]: net.html#net_server_connections
+[`Server.getConnections()`]: net.html#net_server_getconnections_callback
+[`Server.listen({fd: <number>})`]: net.html#net_server_listen_handle_backlog_callback
+[`os.networkInterfaces`]: os.html#os_os_networkinterfaces
+[`os.tmpdir()`]: os.html#os_os_tmpdir
+[`punycode`]: punycode.html
+[`require.extensions`]: globals.html#globals_require_extensions
+[`tls.TLSSocket`]: tls.html#tls_class_tls_tlssocket
+[`tls.CryptoStream`]: tls.html#tls_class_cryptostream
+[`tls.SecurePair`]: tls.html#tls_class_securepair
+[`tls.SecureContext`]: tls.html#tls_tls_createsecurecontext_options
+[`tls.createSecureContext()`]: tls.html#tls_tls_createsecurecontext_options
+[`util`]: util.html
+[`util.debug()`]: util.html#util_util_debug_string
+[`util.error()`]: util.html#util_util_error_strings
+[`util.puts()`]: util.html#util_util_puts_strings
+[`util.print()`]: util.html#util_util_print_strings
+[`util.isArray()`]: util.html#util_util_isarray_object
+[`util.isBoolean()`]: util.html#util_util_isboolean_object
+[`util.isBuffer()`]: util.html#util_util_isbuffer_object
+[`util.isDate()`]: util.html#util_util_isdate_object
+[`util.isError()`]: util.html#util_util_iserror_object
+[`util.isFunction()`]: util.html#util_util_isfunction_object
+[`util.isNull()`]: util.html#util_util_isnull_object
+[`util.isNullOrUndefined()`]: util.html#util_util_isnullorundefined_object
+[`util.isNumber()`]: util.html#util_util_isnumber_object
+[`util.isObject()`]: util.html#util_util_isobject_object
+[`util.isPrimitive()`]: util.html#util_util_isprimitive_object
+[`util.isRegExp()`]: util.html#util_util_isregexp_object
+[`util.isString()`]: util.html#util_util_isstring_object
+[`util.isSymbol()`]: util.html#util_util_issymbol_object
+[`util.isUndefined()`]: util.html#util_util_isundefined_object
+[`util.log()`]: util.html#util_util_log_string
+[`util._extend()`]: util.html#util_util_extend_target_source
+[`worker.suicide`]: cluster.html#cluster_worker_suicide
+[`worker.exitedAfterDisconnect`]: cluster.html#cluster_worker_exitedafterdisconnect