Improve render performance (#3686)

- **PR Description**

Fix a performance regression that I introduced with v0.41: when entering
or leaving staging mode for a file, or when switching from a file that
has only unstaged changes to one that has both staged and unstaged
changes, there was a noticeable lag of about 500ms on my machine. With
the improvements in this PR we get this back down to about 20ms.

1 files changed, 3 insertions, 3 deletions

diff --git a/pkg/gui/context/base_context.go b/pkg/gui/context/base_context.go
index dfcced021..ca04a2fa9 100644
--- a/pkg/gui/context/base_context.go
+++ b/pkg/gui/context/base_context.go
@@ -23,7 +23,7 @@ type BaseContext struct {
 	focusable                   bool
 	transient                   bool
 	hasControlledBounds         bool
-	needsRerenderOnWidthChange  bool
+	needsRerenderOnWidthChange  types.NeedsRerenderOnWidthChangeLevel
 	needsRerenderOnHeightChange bool
 	highlightOnFocus            bool
 
@@ -46,7 +46,7 @@ type NewBaseContextOpts struct {
 	Transient                   bool
 	HasUncontrolledBounds       bool // negating for the sake of making false the default
 	HighlightOnFocus            bool
-	NeedsRerenderOnWidthChange  bool
+	NeedsRerenderOnWidthChange  types.NeedsRerenderOnWidthChangeLevel
 	NeedsRerenderOnHeightChange bool
 
 	OnGetOptionsMap func() map[string]string
@@ -201,7 +201,7 @@ func (self *BaseContext) HasControlledBounds() bool {
 	return self.hasControlledBounds
 }
 
-func (self *BaseContext) NeedsRerenderOnWidthChange() bool {
+func (self *BaseContext) NeedsRerenderOnWidthChange() types.NeedsRerenderOnWidthChangeLevel {
 	return self.needsRerenderOnWidthChange
 }