Rename id parameter to commentID in IssuesService comment methods. (google#886)

Also document which IssueComment fields need to be set in EditComment
method.

This should help improve clarity of the API, and reduce the chance to
mix up the issue vs comment IDs.

Resolves google#885.

Author: dmitshur

github/issues_comments.go

@@ -79,8 +79,8 @@ func (s *IssuesService) ListComments(ctx context.Context, owner string, repo str
 // GetComment fetches the specified issue comment.
 //
 // GitHub API docs: https://developer.github.com/v3/issues/comments/#get-a-single-comment
-func (s *IssuesService) GetComment(ctx context.Context, owner string, repo string, id int64) (*IssueComment, *Response, error) {
-	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, id)
+func (s *IssuesService) GetComment(ctx context.Context, owner string, repo string, commentID int64) (*IssueComment, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, commentID)
 
 	req, err := s.client.NewRequest("GET", u, nil)
 	if err != nil {
@@ -118,10 +118,11 @@ func (s *IssuesService) CreateComment(ctx context.Context, owner string, repo st
 }
 
 // EditComment updates an issue comment.
+// A non-nil comment.Body must be provided. Other comment fields should be left nil.
 //
 // GitHub API docs: https://developer.github.com/v3/issues/comments/#edit-a-comment
-func (s *IssuesService) EditComment(ctx context.Context, owner string, repo string, id int64, comment *IssueComment) (*IssueComment, *Response, error) {
-	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, id)
+func (s *IssuesService) EditComment(ctx context.Context, owner string, repo string, commentID int64, comment *IssueComment) (*IssueComment, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, commentID)
 	req, err := s.client.NewRequest("PATCH", u, comment)
 	if err != nil {
 		return nil, nil, err
@@ -138,8 +139,8 @@ func (s *IssuesService) EditComment(ctx context.Context, owner string, repo stri
 // DeleteComment deletes an issue comment.
 //
 // GitHub API docs: https://developer.github.com/v3/issues/comments/#delete-a-comment
-func (s *IssuesService) DeleteComment(ctx context.Context, owner string, repo string, id int64) (*Response, error) {
-	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, id)
+func (s *IssuesService) DeleteComment(ctx context.Context, owner string, repo string, commentID int64) (*Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/issues/comments/%d", owner, repo, commentID)
 	req, err := s.client.NewRequest("DELETE", u, nil)
 	if err != nil {
 		return nil, err