Add type stubs for mido MIDI library

- Created type stubs for various modules in the mido library including messages, midifiles, parser, ports, sockets, syx, tokenizer, and version.
- Implemented type hints for functions and classes to improve type checking and code clarity.
- Added support for MIDI over TCP/IP in sockets module.
- Included methods for reading and writing SYX files in syx module.
- Enhanced the parser functionality with a dedicated Parser class for MIDI byte streams.
- Established a structure for MIDI file handling with MidiFile and MidiTrack classes.

typings/mido/sockets.pyi

@@ -0,0 +1,43 @@
+"""
+MIDI over TCP/IP.
+"""
+
+import socket
+from typing import Literal, overload
+
+from .ports import BaseIOPort, MultiPort
+
+class PortServer(MultiPort):
+    def __init__(self, host: str, portno: int, backlog: int = 1) -> None: ...
+    @overload
+    def accept(self, block: Literal[True] = True) -> SocketPort:
+        """
+        Accept a connection from a client.
+
+        Will block until there is a new connection, and then return a
+        `SocketPort` object.
+
+        If `block=False`, `None` will be returned if there is no
+        new connection waiting.
+        """
+    @overload
+    def accept(self, block: bool) -> SocketPort | None: ...
+
+class SocketPort(BaseIOPort):
+    def __init__(self, host: str, portno: int, conn: socket.socket | None = ...) -> None: ...
+
+def connect(host: str, portno: int) -> SocketPort:
+    """Connect to a socket port server.
+
+    The return value is a `SocketPort` object connected to another
+    `SocketPort` object at the server end. Messages can be sent either way.
+    """
+
+def parse_address(address: str) -> tuple[str, int]:
+    """Parse and address on the format host:port.
+
+    Returns a tuple (host, port). Raises ValueError if format is
+    invalid or port is not an integer or out of range.
+    """
+
+def format_address(host: str, portno: int) -> str: ...