library: fix some stability annotations

[lukas-code]

This PR updates some stability attributes to correctly reflect when some items actually got stabilized. Found while testing #132481.

core::char / std::char

In #26192, the core::char module got "stabilized" for 1.2.0, but the core crate itself was still unstable until 1.6.0.

In #49698, the std::char module was changed to a re-export of core::char, making std::char appear as "stable since 1.2.0", even though it was already stable in 1.0.0.

By marking core::char as stable since 1.0.0, the docs will show correct versions for both core::char (since 1.6.0) and std::char (since 1.0.0). This is also consistent with the stabilities of similar re-exported modules like core::mem/std::mem for example.

{core,std}::array and {core,std}::array::TryFromSliceError

In #58302, the core::array::TryFromSliceError type got stabilized for 1.34.0, together with TryFrom. At that point the core::array module was still unstable and a std::array re-export didn't exist, but core::array::TryFromSliceError could still be named due to #95956 to existing yet.

Then, core::array got stabilized and std::array got added, first targeting 1.36.0 in #60657, but then getting backported for 1.35.0 in #60838.

This means that core::array and std::array actually got stabilized in 1.35.0 and core::array::TryFromSliceError was accessible through the unstable module in 1.34.0 -- mark them as such so that the docs display the correct versions.

[rustbot]

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[Noratrieb]

I didn't double-check the versions, I'm trusting you that they're correct - they're purely informational anyways.
@bors r+ rollup

[bors]

📌 Commit 2a6a706 has been approved by Noratrieb

It is now in the queue for this repository.