asdf suggests nodejs version is not installed when actually yarn isn't

[nealeu]

In migrating from nodejs 16 to 18, I get the following when trying to run a yarn command (e.g. yarn -v)

$ yarn -v
No preset version installed for command yarn
Please install a version by running one of the following:

asdf install nodejs 18.19.0

or add one of the following versions in your config file at /home/neale/dev/ecco/ecco/.tool-versions
nodejs 16.20.2

This is despite having done as instructed.

The issue was in fact that under nodejs 16, I have yarn installed and there is a yarn shim, but under nodejs 18, I don't have yarn installed.

Doing npm -g install yarn resolves the above error.