allow globbing, and extract queries from .go files

generate/testdata/queries/SimpleQuery.graphql.go

@@ -0,0 +1,35 @@
+package test
+
+// Code generated by github.com/Khan/genqlient, DO NOT EDIT.
+
+import (
+	"github.com/Khan/genqlient/graphql"
+)
+
+type SimpleQueryResponse struct {
+	User SimpleQueryUser `json:"user"`
+}
+
+type SimpleQueryUser struct {
+	Id string `json:"id"`
+}
+
+func SimpleQuery(
+	client graphql.Client,
+) (*SimpleQueryResponse, error) {
+	var retval SimpleQueryResponse
+	err := client.MakeRequest(
+		nil,
+		"SimpleQuery",
+		`
+query SimpleQuery {
+	user {
+		id
+	}
+}
+`,
+		&retval,
+		nil,
+	)
+	return &retval, err
+}