Support NeoForge as a loader (compatible with Forge mods)

TODO: implement support in migrate command

core/pack.go

@@ -198,7 +198,10 @@ func (pack Pack) GetLoaders() (loaders []string) {
 	} else if _, hasFabric := pack.Versions["fabric"]; hasFabric {
 		loaders = append(loaders, "fabric")
 	}
-	if _, hasForge := pack.Versions["forge"]; hasForge {
+	if _, hasNeoForge := pack.Versions["neoforge"]; hasNeoForge {
+		loaders = append(loaders, "neoforge")
+		loaders = append(loaders, "forge") // Backwards-compatible; for now (could be configurable later)
+	} else if _, hasForge := pack.Versions["forge"]; hasForge {
 		loaders = append(loaders, "forge")
 	}
 	return

core/versionutil.go

@@ -51,6 +51,11 @@ var ModLoaders = map[string]ModLoaderComponent{
 		FriendlyName:      "Quilt loader",
 		VersionListGetter: FetchMavenVersionList("https://maven.quiltmc.org/repository/release/org/quiltmc/quilt-loader/maven-metadata.xml"),
 	},
+	"neoforge": {
+		Name:              "neoforge",
+		FriendlyName:      "NeoForge",
+		VersionListGetter: FetchMavenVersionPrefixedListStrip("https://maven.neoforged.net/releases/net/neoforged/forge/maven-metadata.xml", "NeoForge"),
+	},
 }
 
 func FetchMavenVersionList(url string) func(mcVersion string) ([]string, string, error) {