[sections] drop open child sections at diff boundaries

NEWS.md

@@ -8,6 +8,7 @@ Features:
   so that you can manually set an opid on log messages that
   don't have one.  Setting an opid allows messages to show
   up in the gantt chart view.
+* Add support for GitHub Markdown Alerts.
 
 Interface Changes:
 * In the Gantt chart view, pressing `ENTER` will focus on

src/document.sections.cc

@@ -511,6 +511,8 @@ public:
                     break;
                 }
                 case DT_DIFF_FILE_HEADER: {
+                    this->drop_open_children();
+
                     auto sf = this->sw_scanner.to_string_fragment(inner_cap);
                     auto split_res = sf.split_pair(string_fragment::tag1{'\n'});
                     auto file1 = split_res->first.consume_n(4).value();
@@ -550,6 +552,7 @@ public:
                     break;
                 }
                 case DT_DIFF_HUNK_HEADING: {
+                    this->drop_open_children();
                     this->sw_line.get_attrs().emplace_back(
                         line_range{
                             this->sw_range.lr_start
@@ -763,6 +766,16 @@ private:
         std::string is_name;
     };
 
+    void drop_open_children()
+    {
+        while (this->sw_depth > 0) {
+            this->sw_depth -= 1;
+            this->sw_interval_state.pop_back();
+            this->sw_hier_nodes.pop_back();
+            this->sw_container_tokens.pop_back();
+        }
+    }
+
     std::optional<data_scanner::capture_t> flush_values()
     {
         std::optional<data_scanner::capture_t> last_key;
@@ -899,8 +912,8 @@ metadata::possibility_provider(const std::vector<section_key_t>& path)
 namespace fmt {
 auto
 formatter<lnav::document::section_key_t>::format(
-    const lnav::document::section_key_t& key,
-    fmt::format_context& ctx) -> decltype(ctx.out()) const
+    const lnav::document::section_key_t& key, fmt::format_context& ctx)
+    -> decltype(ctx.out()) const
 {
     return key.match(
         [this, &ctx](const std::string& str) {

src/md2attr_line.cc

@@ -326,7 +326,7 @@ md2attr_line::leave_block(const md4cpp::event_handler::block& bl)
             attr_line_t replacement;
 
             if (md[1] == "NOTE") {
-                replacement.append("\u24d8 Note\n"_footnote_border);
+                replacement.append("\u24d8  Note\n"_footnote_border);
                 border_role = role_t::VCR_FOOTNOTE_BORDER;
             } else if (md[1] == "TIP") {
                 replacement.append(":bulb:"_emoji)