[subprocess] Consistency between text and universal_newlines

[srittau]

text can't be False if universal_newlines is True.

Also document the overloads.

[srittau]

Errors are due to #15653.

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

mypy (https://github.com/python/mypy)
  error: INTERNAL ERROR -- Please try using mypy master on GitHub:

dulwich (https://github.com/dulwich/dulwich)
+ dulwich/filters.py:190: error: Returning Any from function declared to return "bytes"  [no-any-return]

pandas (https://github.com/pandas-dev/pandas)
- pandas/core/computation/ops.py:328: error: Need type annotation for "_binary_ops_dict" (hint: "_binary_ops_dict: dict[<type>, <type>] = ...")  [var-annotated]

prefect (https://github.com/PrefectHQ/prefect)
- src/prefect/cli/shell.py:76: note:     def [AnyStr: (str, bytes)] Popen(args: str | bytes | PathLike[str] | PathLike[bytes] | Sequence[str | bytes | PathLike[str] | PathLike[bytes]], bufsize: int = ..., executable: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., stdin: int | IO[Any] | None = ..., stdout: int | IO[Any] | None = ..., stderr: int | IO[Any] | None = ..., preexec_fn: Callable[[], object] | None = ..., close_fds: bool = ..., shell: bool = ..., cwd: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., env: Mapping[bytes, str | bytes | PathLike[str] | PathLike[bytes]] | Mapping[str, str | bytes | PathLike[str] | PathLike[bytes]] | None = ..., universal_newlines: bool | None = ..., startupinfo: Any | None = ..., creationflags: int = ..., restore_signals: bool = ..., start_new_session: bool = ..., pass_fds: Collection[int] = ..., *, text: Literal[True], encoding: str | None = ..., errors: str | None = ..., user: str | int | None = ..., group: str | int | None = ..., extra_groups: Iterable[str | int] | None = ..., umask: int = ..., pipesize: int = ...) -> Popen[str]
+ src/prefect/cli/shell.py:76: note:     def [AnyStr: (str, bytes)] Popen(args: str | bytes | PathLike[str] | PathLike[bytes] | Sequence[str | bytes | PathLike[str] | PathLike[bytes]], bufsize: int = ..., executable: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., stdin: int | IO[Any] | None = ..., stdout: int | IO[Any] | None = ..., stderr: int | IO[Any] | None = ..., preexec_fn: Callable[[], object] | None = ..., close_fds: bool = ..., shell: bool = ..., cwd: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., env: Mapping[bytes, str | bytes | PathLike[str] | PathLike[bytes]] | Mapping[str, str | bytes | PathLike[str] | PathLike[bytes]] | None = ..., universal_newlines: Literal[True] | None = ..., startupinfo: Any | None = ..., creationflags: int = ..., restore_signals: bool = ..., start_new_session: bool = ..., pass_fds: Collection[int] = ..., *, text: Literal[True], encoding: str | None = ..., errors: str | None = ..., user: str | int | None = ..., group: str | int | None = ..., extra_groups: Iterable[str | int] | None = ..., umask: int = ..., pipesize: int = ...) -> Popen[str]