Add note in docs on score_weight config if using a non-default `spa…

…ns_key` for SpanCat (explosion#13093)

* Add note on score_weight if using a non-default span_key for SpanCat.

* Fix formatting.

* Fix formatting.

* Fix typo.

* Use warning infobox.

* Fix infobox formatting.

website/docs/api/spancategorizer.mdx

@@ -75,8 +75,7 @@ architectures and their arguments and hyperparameters.
 <Infobox variant="warning">
 
 If you set a non-default value for `spans_key`, you'll have to update
-`[training.score_weights]` as well so that weights are computed properly. E. g.
-for `spans_key == "myspankey"`, include this in your config:
+`[training.score_weights]` as well so that weights are computed properly. E. g. for `span_key == "myspankey"`, include this in your config:
 
 ```ini
 [training.score_weights]