PR 239 update: Adding more logging for the initial generate setup (#246)

This is just a tweak to #239 to update the snapshots.
I have:
- [X] Written a clear PR title and description (above)
- [X] Signed the [Khan Academy CLA](https://www.khanacademy.org/r/cla)
- [X] Added tests covering my changes, if applicable
- [X] Included a link to the issue fixed, if applicable
- [X] Included documentation, for new features
- [ ] Added an entry to the changelog

Signed-off-by: Steve Coffman <[email protected]>
Co-authored-by: Sam Wallace <[email protected]>

generate/convert.go

@@ -524,7 +524,8 @@ func (g *generator) convertDefinition(
 
 		// (If you had an entry in bindings, we would have returned it above.)
 		return nil, errorf(
-			pos, `unknown scalar %v: please add it to "bindings" in genqlient.yaml`, def.Name)
+			pos, "unknown scalar %v: please add it to \"bindings\" in genqlient.yaml"+
+				"\nExample: https://github.com/Khan/genqlient/blob/main/example/genqlient.yaml#L12", def.Name)
 	default:
 		return nil, errorf(pos, "unexpected kind: %v", def.Kind)
 	}