Fix searching with special characters

Caps/ContentView.swift

@@ -65,9 +65,7 @@ struct ContentView: View {
     private var selectedCapToShowImages: Cap?
 
     var filteredCaps: [Cap] {
-        let text = searchString
-            .trimmingCharacters(in: .whitespacesAndNewlines)
-            .lowercased()
+        let text = searchString.clean
         guard text != "" else {
             return Array(database.caps.values)
         }

Caps/Data/Cap.swift

@@ -143,15 +143,6 @@ extension Cap: Hashable {
     }
 }
 
-// MARK: String extension
-
-private extension String {
-
-    var clean: String {
-        return lowercased().replacingOccurrences(of: "[^a-z0-9 ]", with: "", options: .regularExpression)
-    }
-}
-
 // MARK: Int extension
 
 private extension Int {

Caps/Extensions/String+Extensions.swift

@@ -0,0 +1,10 @@
+import Foundation
+
+extension String {
+
+    var clean: String {
+        lowercased()
+            .replacingOccurrences(of: "[^a-z0-9 ]", with: "", options: .regularExpression)
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+}