Add linter troubleshooting page when using outdated linter

[BD103]

How can the CLI or linter's documentation be improved?

As a follow up to #614 (and related to #528), I'd like to expand on the troubleshooting section for when the linter uses an old version of rustc.

Specifically, errors where the rust-version is incompatible:

❯ bevy lint
error: rustc 1.86.0-nightly is not supported by the following packages:
  bevy@0.17.0-rc.1 requires rustc 1.88.0
  bevy_skein@0.3.0-rc.1 requires rustc 1.88.0
  sysinfo@0.37.0 requires rustc 1.88
Either upgrade rustc or select compatible dependency versions with
`cargo update <name>@<current-ver> --precise <compatible-ver>`
where `<compatible-ver>` is the latest version supporting rustc 1.86.0-nightly

Check failed: exit status: 101.
error: command `bevy_lint --profile dev` exited with status code exit status: 101

Or errors where the package uses features that the linter doesn't think are stabilized:

0\src\egui_utils.rs:396:24
    |
396 | && let Some(newline) = language_start.find('\n')
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #53667 https://github.com/rust-lang/rust/issues/53667 for more information
    = help: add #![feature(let_chains)] to the crate attributes to enable
    = note: this compiler was built on 2025-04-02; consider upgrading it if it is out of date

Both of these errors can occur when the linter's supported Rust version is older than stable Rust. This usually happens when a linter release is older than 18 weeks.