Bump golangci-lint and (max) Go versions (#219)

Lint is failing with some inscrutable panic (on a commit with no code
changes). Let's try bumping the version in case they fixed it.

Additionally, the new version's github action uses Go 1.19, which means
it pulls in gofmt updates to match the new [doc-comment formatting rules][1].
So I added Go 1.19 to our list of versions to test (fixes #216)
and updated some of our doc-comments to format better in the
new world (mostly using the new link syntax).

[1]: https://go.dev/doc/comment

Test plan: make lint

generate/names.go

@@ -81,9 +81,11 @@ package generate
 //   can collide.
 // All cases seem fairly rare in practice; eventually we'll likely allow users
 // the ability to specify their own names, which they could use to avoid this
-// (see https://github.com/Khan/genqlient/issues/12).
+// (see [issue #12]).
 // TODO(benkraft): We should probably at least try to detect it and bail.
 //
+// [issue #12]: https://github.com/Khan/genqlient/issues/12
+//
 // To implement all of the above, as we traverse the operation (and schema) in
 // convert.go, we keep track of a list of parts to prefix to our type-names.
 // The list always ends with a field, not a type; and we extend it when