feat: jump to a line with counted g

tests/line_jump.rs

@@ -0,0 +1,50 @@
+use vamp::editor::{Cursor, Editor, Effect, Input, Mode};
+fn editor() -> Editor {
+    let mut editor = Editor::open(None, vec![]).unwrap();
+    editor
+        .apply(vec![Effect::Replace(
+            "first\n  e\u{301}second\n\tthird".into(),
+        )])
+        .unwrap();
+    editor
+}
+fn keys(editor: &mut Editor, text: &str) {
+    for key in text.chars() {
+        editor.handle(Input::Char(key));
+    }
+}
+#[test]
+fn counted_g_is_one_based_clamps_and_leaves_bare_prefixes_intact() {
+    let mut editor = editor();
+    let revision = editor.text_revision();
+    keys(&mut editor, "2g");
+    assert_eq!(editor.cursor(), Cursor { row: 1, column: 2 });
+    assert_eq!(editor.count(), None);
+    keys(&mut editor, "999999999999999999999999999999999g");
+    assert_eq!(editor.cursor(), Cursor { row: 2, column: 1 });
+    keys(&mut editor, "1g");
+    assert_eq!(editor.cursor().row, 0);
+    keys(&mut editor, "gb");
+    assert_eq!(editor.cursor().row, 2);
+    keys(&mut editor, "gt");
+    assert_eq!(editor.cursor().row, 0);
+    assert_eq!(editor.text_revision(), revision);
+}
+#[test]
+fn counted_g_extends_visual_selection_and_respects_g_overrides() {
+    let mut editor = editor();
+    keys(&mut editor, "v3g");
+    assert_eq!(editor.mode(), Mode::Visual);
+    assert_eq!(editor.cursor(), Cursor { row: 2, column: 1 });
+    assert_eq!(editor.selections()[0].start, Cursor { row: 0, column: 0 });
+    editor.handle(Input::Escape);
+    keys(&mut editor, "gt");
+    editor.bind("normal", "g", None).unwrap();
+    keys(&mut editor, "2g");
+    assert_eq!(editor.cursor().row, 0);
+    editor
+        .bind("normal", "g", Some("core.down".into()))
+        .unwrap();
+    keys(&mut editor, "2g");
+    assert_eq!(editor.cursor().row, 2);
+}