docs: Update the Zed editor integration

[lingyaochu]

Summary

According to the PR zed-industries/zed#50662, the LSP adapters registry logic has been updated, and the corresponding documentation in Zed has changed as well.

This PR syncs the ty side to align with these changes.

Test Plan

No test needed.

[MichaReiser]

Can you say more about why you removed .... Should we rephrase the comment instead of removing all other language servers (so that the documentation matches Zed's documentation in https://github.com/zed-industries/zed/pull/50662/changes)

[lingyaochu]

I removed the "..." because while its underlying logic (enabling all remaining registered adapters) hasn't changed, Zed's registry behavior has. Previously, adapters like pylsp and pyright and ty were lazy-loaded and didn't appear in the registry unless explicitly invoked. Because of this, a configuration like ["ty", "!basedpyright", "..."] would coincidentally only enable ruff, making the old documentation’s claim that ... meant "keep defaults" appear correct in practice.

However, after the registry logic change in zed-industries/zed#50662, all five Python adapters are now registered upfront. This means keeping the ellipsis would now result in an effective configuration of ["ty", "!basedpyright", "ruff", "pylsp", "pyright"], spawning redundant language servers that users don't actually want. While Zed’s own documentation might retain the "..." to explain the feature's mechanics, I believe our documentation for ty should prioritize providing a clean, "copy-pasteable" configuration. By removing the ellipsis, we ensure that users get exactly what they expect—ty enabled and basedpyright disabled—without any unintended side effects or performance overhead from extra LSPs.