feat: add config option keybind_mode with workaround ignore_alt_text_modifiers

This option may be set to ignore_alt_text_modifiers to enable a workround
for #417

src/config.zig

@@ -60,6 +60,8 @@ centered_view_min_screen_width: usize = 145,
 
 lsp_output: enum { quiet, verbose } = .quiet,
 
+keybind_mode: KeybindMode = .normal,
+
 include_files: []const u8 = "",
 
 const default_actions = [_]IdleAction{};
@@ -139,3 +141,8 @@ pub const PaneStyle = enum {
     panel,
     editor,
 };
+
+pub const KeybindMode = enum {
+    normal,
+    ignore_alt_text_modifiers,
+};