feat: add toggle_gutter_diffs command and gutter_diffs config option

closes #533

src/config.zig

@@ -7,6 +7,7 @@ input_mode: []const u8 = "flow",
 gutter_line_numbers_mode: ?LineNumberMode = null,
 gutter_line_numbers_style: DigitStyle = .ascii,
 gutter_symbols: bool = true,
+gutter_diffs: bool = true,
 gutter_width_mode: GutterWidthMode = .local,
 gutter_width_minimum: usize = 4,
 gutter_width_maximum: usize = 8,

src/tui/editor_gutter.zig

@@ -262,6 +262,7 @@ inline fn render_line_highlight(self: *Self, pos: usize, theme: *const Widget.Th
 }
 
 inline fn render_diff_symbols(self: *Self, diff_symbols: *[]Diff, pos: usize, linenum_: usize, theme: *const Widget.Theme) void {
+    if (!tui.config().gutter_diffs) return;
     const linenum = linenum_ - 1;
     if (diff_symbols.len == 0) return;
     while ((diff_symbols.*)[0].line < linenum) {

src/tui/mainview.zig

@@ -1048,6 +1048,13 @@ const cmds = struct {
     }
     pub const toggle_inline_diagnostics_meta: Meta = .{ .description = "Toggle display of diagnostics inline" };
 
+    pub fn toggle_gutter_diffs(_: *Self, _: Ctx) Result {
+        const config = tui.config_mut();
+        config.gutter_diffs = !config.gutter_diffs;
+        try tui.save_config();
+    }
+    pub const toggle_gutter_diffs_meta: Meta = .{ .description = "Toggle gutter diff markers" };
+
     pub fn goto_next_file_or_diagnostic(self: *Self, ctx: Ctx) Result {
         if (self.is_panel_view_showing(filelist_view)) {
             switch (self.file_list_type) {