Add API to get issue/pull comments and events (timeline) (#17403)

* Add API to get issue/pull comments and events (timeline)
Adds an API to get both comments and events in one endpoint with all required data.
Closes go-gitea/gitea#13250

* Fix swagger

* Don't show code comments (use review api instead)

* fmt

* Fix comment

* Time -> TrackedTime

* Use var directly

* Add logger

* Fix lint

* Fix test

* Add comments

* fmt

* [test] get issue directly by ID

* Update test

* Add description for changed refs

* Fix build issues + lint

* Fix build

* Use string enums

* Update swagger

* Support `page` and `limit` params

* fmt + swagger

* Use global slices

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/references/references.go

@@ -49,6 +49,13 @@ var (
 	giteaHostInit         sync.Once
 	giteaHost             string
 	giteaIssuePullPattern *regexp.Regexp
+
+	actionStrings = []string{
+		"none",
+		"closes",
+		"reopens",
+		"neutered",
+	}
 )
 
 // XRefAction represents the kind of effect a cross reference has once is resolved
@@ -65,6 +72,10 @@ const (
 	XRefActionNeutered // 3
 )
 
+func (a XRefAction) String() string {
+	return actionStrings[a]
+}
+
 // IssueReference contains an unverified cross-reference to a local issue or pull request
 type IssueReference struct {
 	Index   int64