Add email.quoprimime stub (#6664)

Co-authored-by: Akuli <akuviljanen17@gmail.com>

stdlib/email/quoprimime.pyi

@@ -0,0 +1,13 @@
+def header_check(octet: int) -> bool: ...
+def body_check(octet: int) -> bool: ...
+def header_length(bytearray: bytes) -> int: ...
+def body_length(bytearray: bytes) -> int: ...
+def unquote(s: str | bytes) -> str: ...
+def quote(c: str | bytes) -> str: ...
+def header_encode(header_bytes: bytes, charset: str = ...) -> str: ...
+def body_encode(body: str, maxlinelen: int = ..., eol: str = ...) -> str: ...
+def decode(encoded: str, eol: str = ...) -> str: ...
+def header_decode(s: str) -> str: ...
+
+body_decode = decode
+decodestring = decode