Extract a method CommitFilesContext.ReInit

Right now it doesn't do very much yet, but it's still worth it even in this
state, I'd say. The function is going to become a bit longer in the next commit,
though.

pkg/gui/context/commit_files_context.go

@@ -78,3 +78,9 @@ func (self *CommitFilesContext) GetDiffTerminals() []string {
 func (self *CommitFilesContext) ModelSearchResults(searchStr string, caseSensitive bool) []gocui.SearchPosition {
 	return nil
 }
+
+func (self *CommitFilesContext) ReInit(ref types.Ref) {
+	self.SetRef(ref)
+	self.SetTitleRef(ref.Description())
+	self.GetView().Title = self.Title()
+}

pkg/gui/controllers/helpers/refresh_helper.go

@@ -285,9 +285,7 @@ func (self *RefreshHelper) refreshCommitsAndCommitFiles() {
 		// For now the awkwardness remains.
 		commit := self.c.Contexts().LocalCommits.GetSelected()
 		if commit != nil && commit.RefName() != "" {
-			self.c.Contexts().CommitFiles.SetRef(commit)
-			self.c.Contexts().CommitFiles.SetTitleRef(commit.Description())
-			self.c.Contexts().CommitFiles.GetView().Title = self.c.Contexts().CommitFiles.Title()
+			self.c.Contexts().CommitFiles.ReInit(commit)
 			_ = self.refreshCommitFilesContext()
 		}
 	}

pkg/gui/controllers/switch_to_diff_files_controller.go

@@ -71,9 +71,8 @@ func (self *SwitchToDiffFilesController) enter(ref types.Ref) error {
 		}
 	}
 
+	commitFilesContext.ReInit(ref)
 	commitFilesContext.SetSelection(0)
-	commitFilesContext.SetRef(ref)
-	commitFilesContext.SetTitleRef(ref.Description())
 	commitFilesContext.SetCanRebase(canRebase)
 	commitFilesContext.SetParentContext(self.context)
 	commitFilesContext.SetWindowName(self.context.GetWindowName())