Comments to show intended structure use

src/github.com/matrix-org/go-neb/services/google/google.go

@@ -123,7 +123,7 @@ func (s *Service) cmdGoogleImgSearch(client *gomatrix.Client, roomID, userID str
 	// FIXME -- Sometimes upload fails with a cryptic error - "msg=Upload request failed code=400"
 	resUpload, err := client.UploadLink(imgURL)
 	if err != nil {
-		return nil, fmt.Errorf("Failed to upload Google image to matrix: %s", err.Error())
+		return nil, fmt.Errorf("Failed to upload Google image at URL %s (content type %s) to matrix: %s", imgURL, searchResult.Mime, err.Error())
 	}
 
 	return gomatrix.ImageMessage{

src/github.com/matrix-org/go-neb/services/wikipedia/wikipedia.go

@@ -21,14 +21,17 @@ const maxExtractLength = 1024 // Max length of extract string in bytes
 
 var httpClient = &http.Client{}
 
+// Search results (returned by search query)
 type wikipediaSearchResults struct {
 	Query wikipediaQuery `json:"query"`
 }
 
+// Wikipeda pages returned in search results
 type wikipediaQuery struct {
 	Pages map[string]wikipediaPage `json:"pages"`
 }
 
+// Representation of an individual wikipedia page
 type wikipediaPage struct {
 	PageID    int64  `json:"pageid"`
 	NS        int    `json:"ns"`