Use role :const: for referencing module constants

[serhiy-storchaka]

While technically Python modules are mutable and every name can be overridden, some names are not intended to be changed. Sphinx has a special directive for this: :const:. I think that it is better to use semantically more specific :const: instead of general :data: in these cases.

First of all it is all-uppercase names, but there are exceptions: curses.LINES and curses.COLS are changed after terminal changes size. But some lowercase names like os.sep and string.ascii_letters are also clearly constants.

Linked PRs

• gh-106909: Use role :const: for referencing module constants #106910
• [3.12] gh-106909: Use role :const: for referencing module constants (GH-106910) #106956
• [3.11] gh-106909: Use role :const: for referencing module constants (GH-106910) #106957

[erlend-aasland]

Why not replace them with :py:const:?