Update typescript to 4.6

[rmunn]

Description

Update Typescript to 4.6 so it matches the Typescript version used in Playwright and Svelte, to avoid future problems.

Fixes #1325.

Type of Change

Only keep lines below that describe this change, then delete the rest.

• Bug fix (non-breaking change which fixes an issue)

Testing on your branch

Please describe how to test and/or verify your changes. Provide instructions so we can reproduce. Please also provide relevant test data as necessary. These instructions will be used for QA testing below.

• Run make and ensure the site still builds

Checklist

• I have performed a self-review of my own code
• I have reviewed the title/description of this PR which will be used as the squashed PR commit message
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works

qa.languageforge.org testing

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• Reviewer1 (YYYY-MM-DD HH:MM)
• Reviewer2 (YYYY-MM-DD HH:MM)

[rmunn]

There's also a change to the Dockerfile for next-app in here, because while buildx appears to build that file as-is just fine, my Docker installation (which isn't using buildx) complains about the missing / in a COPY command, and says "Since that's a directory, you must include a trailing slash". So I added it in this PR because it's a very small change and likely won't cause any merge conflicts. I can remove it if it matters.

[github-actions]

Unit Test Results

373 tests   373 ✔️  14s ⏱️
    1 suites      0 💤
    1 files        0 ❌

Results for commit fb603a6.

[megahirt]

There's also a change to the Dockerfile for next-app in here, because while buildx appears to build that file as-is just fine, my Docker installation (which isn't using buildx) complains about the missing / in a COPY command, and says "Since that's a directory, you must include a trailing slash". So I added it in this PR because it's a very small change and likely won't cause any merge conflicts. I can remove it if it matters.

I think it's fine to fix it up.

For the record, everyone should have export DOCKER_BUILDKIT=1 in their environment. This only affects Linux systems that installed Docker as a package. The "Docker for Windows/Mac/Linux" installation does this automatically.

[megahirt]

LGTM this is a welcome upgrade, Robin!