go_deps: Support default naming convention override for Bazel modules

This unblocks using the `build_stackb_rules_proto` module with Gazelle and default settings, as it doesn't generate `go_default_library` targets.

Note that a manually applied `gazelle_override` still results in the Go module being preferred over the Bazel module, so this currently only works with default overrides.

internal/bzlmod/default_gazelle_overrides.bzl

@@ -86,6 +86,9 @@ DEFAULT_DIRECTIVES_BY_PATH = {
         # in go files are generated by gogo proto. Resolving to the gogo proto target preserves the behavior of Go modules.
         "gazelle:resolve go github.com/mwitkow/go-proto-validators @com_github_mwitkow_go_proto_validators//:validators_gogo",
     ],
+    "github.com/stackb/rules_proto": [
+        "gazelle:go_naming_convention import",
+    ],
     "google.golang.org/grpc": [
         "gazelle:proto disable",
     ],

language/go/config.go

@@ -534,17 +534,23 @@ Update io_bazel_rules_go to a newer version in your WORKSPACE file.`
 		repoNamingConvention := map[string]namingConvention{}
 		for _, repo := range c.Repos {
 			if repo.Kind() == "go_repository" {
+				var name string
+				if apparentName := c.ModuleToApparentName(repo.AttrString("module_name")); apparentName != "" {
+					name = apparentName
+				} else {
+					name = repo.Name()
+				}
 				if attr := repo.AttrString("build_naming_convention"); attr == "" {
 					// No naming convention specified.
 					// go_repsitory uses importAliasNamingConvention by default, so we
 					// could use whichever name.
 					// resolveExternal should take that as a signal to follow the current
 					// naming convention to avoid churn.
-					repoNamingConvention[repo.Name()] = importAliasNamingConvention
+					repoNamingConvention[name] = importAliasNamingConvention
 				} else if nc, err := namingConventionFromString(attr); err != nil {
-					log.Printf("in go_repository named %q: %v", repo.Name(), err)
+					log.Printf("in go_repository named %q: %v", name, err)
 				} else {
-					repoNamingConvention[repo.Name()] = nc
+					repoNamingConvention[name] = nc
 				}
 			}
 		}