Typo in JSON serialization error message.

[alex-ozdemir]

I stumbled upon a small typo while reading the source.

By submitting this pull request

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I confirm that I've made a best effort attempt to update all relevant documentation.

[davidbarsky]

Thanks for opening this PR! This change looks good to me—I'll try to see why the build is failing on nightly, while it's succeeding on stable.

[alex-ozdemir]

This failure is actually unrelated to this PR.

A few days ago the doc-dude, Giullaume landed this PR, which made the missing_docs warning stop ignoring macro_rules macro definitions. Since y'all have #[deny(warnings)] on in the lambda-runtime crate, and this macro is missing documentation, this caused the build to fail on nightly.

I've added documentation for that macro in this PR.

[davidbarsky]

This failure is actually unrelated to this PR.

Yep, you're right! I meant to say “investigate what happened in rustc”, but thanks for doing that research for me!

[davidbarsky]

Once #71 is merged, I'll restart this build—I don't think that a rebase is necessary. Thanks for your help!

[davidbarsky]

Thanks! Just merged these changes. Also, I'm sorry about the delay! I'll ask the administrators of the awslabs organization if email notifications can be turned on.