When previewing the site, warnings are printed out:
```
WARN Shortcode "tabpane": duplicate tab-persistence key "yaml" detected, disabling persistence to avoid multiple tab display.
```
This PR fixes these issues.
Co-authored-by: Kurtis Van Gent <31518063+kurtisvg@users.noreply.github.com>
Update `spanner-sql` kind in example. It was previously updated
throughout the doc, except for the example.
It should be `spanner-sql` instead of `spanner`.
Fixes#302
