Fix LSP completion transform of path-likes when insertText missing

[krassowski]

References

Fixes #832

Code changes

User-facing changes

Completion of import { Signal } from @lumino/<tab> will work correctly.

Backwards-incompatible changes

Chores

• linted
• tested
• documented
• changelog entry

[github-actions]

👈 Launch a binder notebook on branch krassowski/jupyterlab-lsp/completion/handle-missing-insertText-in-paths

[krassowski]

@meeseeksdev please backport to 3.x

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 3.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 1552c1c22c832f33a9c63493d70a72031dd84a59

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #833: Fix LSP completion transform of path-likes when `insertText` missing'

4. Push to a named branch:

git push YOURFORK 3.x:auto-backport-of-pr-833-on-3.x

5. Create a PR against branch 3.x, I would have named this PR:

"Backport PR #833 on branch 3.x (Fix LSP completion transform of path-likes when insertText missing)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.