Fix truncation of branches when scrolling branches panel to the left (#4483)

- **PR Description**

Truncation of long branch names didn't take the horizontal scroll
position into account; when scrolling the panel to the left using `H`,
the long names were truncated way before the right edge of the view.

Author: stefanhaller

pkg/gui/context/branches_context.go

@@ -30,7 +30,7 @@ func NewBranchesContext(c *ContextCommon) *BranchesContext {
 			c.State().GetItemOperation,
 			c.State().GetRepoState().GetScreenMode() != types.SCREEN_NORMAL,
 			c.Modes().Diffing.Ref,
-			c.Views().Branches.InnerWidth(),
+			c.Views().Branches.InnerWidth()+c.Views().Branches.OriginX(),
 			c.Tr,
 			c.UserConfig(),
 			c.Model().Worktrees,

pkg/gui/controllers/list_controller.go

@@ -74,6 +74,9 @@ func (self *ListController) scrollHorizontal(scrollFunc func()) error {
 	scrollFunc()
 
 	self.context.HandleFocus(types.OnFocusOpts{})
+	if self.context.NeedsRerenderOnWidthChange() == types.NEEDS_RERENDER_ON_WIDTH_CHANGE_WHEN_WIDTH_CHANGES {
+		self.context.HandleRender()
+	}
 	return nil
 }