Remove duplicate definitions in sub-classes (#8594)

stdlib/html/parser.pyi

@@ -7,8 +7,6 @@ class HTMLParser(ParserBase):
     def __init__(self, *, convert_charrefs: bool = ...) -> None: ...
     def feed(self, data: str) -> None: ...
     def close(self) -> None: ...
-    def reset(self) -> None: ...
-    def getpos(self) -> tuple[int, int]: ...
     def get_starttag_text(self) -> str | None: ...
     def handle_starttag(self, tag: str, attrs: list[tuple[str, str | None]]) -> None: ...
     def handle_endtag(self, tag: str) -> None: ...
@@ -19,7 +17,6 @@ class HTMLParser(ParserBase):
     def handle_comment(self, data: str) -> None: ...
     def handle_decl(self, decl: str) -> None: ...
     def handle_pi(self, data: str) -> None: ...
-    def unknown_decl(self, data: str) -> None: ...
     CDATA_CONTENT_ELEMENTS: tuple[str, ...]
     def check_for_whole_start_tag(self, i: int) -> int: ...  # undocumented
     def clear_cdata_mode(self) -> None: ...  # undocumented