chore: add some comments in snapshot client

provider/snapshot/client.go

@@ -7,6 +7,7 @@ import (
 	"github.com/Khan/genqlient/graphql"
 )
 
+// Command to generate the client code in operation.go.
 //go:generate go run --mod=mod github.com/Khan/[email protected]
 
 const (
@@ -18,31 +19,41 @@ const (
 	ProposalStateClosed = "closed"
 )
 
+// Use _ to make sure we implement the interface.
 var _ graphql.Doer = (*client)(nil)
 
+// A graphql.Doer that adds the X-API-KEY header to requests.
 type client struct {
 	httpClient *http.Client
 	apiKey     string
 }
 
+// Do implements [graphql.Doer].
 func (c *client) Do(request *http.Request) (*http.Response, error) {
+	// add the X-API-KEY header if it's set.
 	if c.apiKey != "" {
 		request.Header.Set("X-API-KEY", c.apiKey)
 	}
 
+	// do the request
 	return c.httpClient.Do(request)
 }
 
+// NewClient a function that can be used to configure a [client] with options.
+// Options are applied in the order they are passed to the function
 func NewClient(endpoint string, options ...Option) (graphql.Client, error) {
+	// build a default client
 	instance := client{
 		httpClient: http.DefaultClient,
 	}
 
+	// Apply options.
 	for _, option := range options {
 		if err := option(&instance); err != nil {
 			return nil, fmt.Errorf("apply option: %w", err)
 		}
 	}
 
+	// Return the client
 	return graphql.NewClient(endpoint, &instance), nil
 }

provider/snapshot/option.go

@@ -1,7 +1,9 @@
 package snapshot
 
+// Option is a function that can be used to configure a [client].
 type Option func(client *client) error
 
+// WithAPIKey is an [Option] that can be used to set the X-API-KEY header for requests.
 func WithAPIKey(apiKey string) Option {
 	return func(client *client) error {
 		client.apiKey = apiKey