Insert gemini protocol into host-only URLs

Gemini-iOS/NavigationBarView.swift

@@ -77,8 +77,11 @@ class NavigationBarView: UIView {
     
     @objc private func commitURL() {
         textField.resignFirstResponder()
-        if let text = textField.text, let url = URL(string: text) {
+        if let text = textField.text, var components = URLComponents(string: text) {
-            navigator.changeURL(url)
+            if components.scheme == nil {
+                components.scheme = "gemini"
+            }
+            navigator.changeURL(components.url!)
         } else {
             textField.text = navigator.displayURL
         }