RustDoc: remove the redundant unstable option "--linker"

[andjo403]

while working on #63638 i have noticed the there is a conflict between the "-C linker" and the "--linker" option where the later overrides the former.

but as the --linker flag is unstable I think that it shall be removed as is it confusing where all other "-C" options works but not the linker one.

[mati865]

Are you sure -C linker works for rustdoc?
I thought rustdoc only cares about --linker and rustc about -C linker.

[andjo403]

now rustdoc -C linker do not work but if the --linker option is removed the -C linker will work as expected

[mati865]

if the --linker option is removed the -C linker will work as expected

I think it'd have to be implemented in rustdoc first.

[andjo403]

yes that is what this issue is about remove the --linker option from rustdoc and use the -C linker option instead

[andjo403]

@petrochenkov do you know if there is some process to remove the unstable linker option from rustdoc as you added it in #45191

[petrochenkov]

do you know if there is some process to remove the unstable linker option from rustdoc

I don't know ¯_(ツ)_/¯
If it's unstable and there's a replacement, then it can probable be just removed?
cc @rust-lang/rustdoc

[GuillaumeGomez]

If it's not stable, then it's fine. :)