Settings UI: Fix spelling error and make spell checker happy (#41403)

## Summary of the Pull Request

- Renames `NavigatablePage` to `NavigablePage` to fix a spelling error.
- Reverts related entries in `exclude.txt` that triggered a forbidden
pattern error in the spell checker.
- The spell checker does not allow PascalCase words like
`NavigatablePage` in `exclude.txt` because of its automatic casing
rules.

 
Regression: #41285

---------

Co-authored-by: vanzue <vanzue@outlook.com>

src/settings-ui/Settings.UI/SettingsXAML/Views/GeneralPage.xaml

@@ -1,4 +1,4 @@
-<local:NavigatablePage
+<local:NavigablePage
     x:Class="Microsoft.PowerToys.Settings.UI.Views.GeneralPage"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
@@ -12,10 +12,10 @@
     AutomationProperties.LandmarkType="Main"
     mc:Ignorable="d">
 
-    <local:NavigatablePage.Resources>
+    <local:NavigablePage.Resources>
         <converters:UpdateStateToBoolConverter x:Key="UpdateStateToBoolConverter" />
         <converters:StringToInfoBarSeverityConverter x:Key="StringToInfoBarSeverityConverter" />
-    </local:NavigatablePage.Resources>
+    </local:NavigablePage.Resources>
 
     <controls:SettingsPageControl x:Uid="General" ModuleImageSource="ms-appx:///Assets/Settings/Modules/PT.png">
         <controls:SettingsPageControl.ModuleContent>
@@ -517,4 +517,4 @@
             <controls:PageLink x:Uid="OpenSource_Notice" Link="https://github.com/microsoft/PowerToys/blob/main/NOTICE.md" />
         </controls:SettingsPageControl.SecondaryLinks>
     </controls:SettingsPageControl>
-</local:NavigatablePage>
+</local:NavigablePage>