Fix leading whitespace after hard break (#348)

diff --git a/lib/src/html_renderer.dart b/lib/src/html_renderer.dart
index 78ce279..761442d 100644
--- a/lib/src/html_renderer.dart
+++ b/lib/src/html_renderer.dart
@@ -37,7 +37,7 @@
 }
 
 /// Renders [nodes] to HTML.
-String renderToHtml(List<Node?> nodes) => HtmlRenderer().render(nodes);
+String renderToHtml(List<Node> nodes) => HtmlRenderer().render(nodes);
 
 const _blockTags = [
   'blockquote',
@@ -82,12 +82,12 @@
 
   HtmlRenderer();
 
-  String render(List<Node?> nodes) {
+  String render(List<Node> nodes) {
     buffer = StringBuffer();
     uniqueIds = <String>{};
 
     for (final node in nodes) {
-      node!.accept(this);
+      node.accept(this);
     }
 
     return buffer.toString();
@@ -96,7 +96,7 @@
   @override
   void visitText(Text text) {
     var content = text.text;
-    if (const ['p', 'li'].contains(_lastVisitedTag)) {
+    if (const ['br', 'p', 'li'].contains(_lastVisitedTag)) {
       var lines = LineSplitter.split(content);
       content = content.contains('<pre>')
           ? lines.join('\n')
diff --git a/test/common_mark/hard_line_breaks.unit b/test/common_mark/hard_line_breaks.unit
index ebf2c4b..a8de1e7 100644
--- a/test/common_mark/hard_line_breaks.unit
+++ b/test/common_mark/hard_line_breaks.unit
@@ -21,13 +21,13 @@
      bar
 <<<
 <p>foo<br />
-     bar</p>
+bar</p>
 >>> Hard line breaks - 634
 foo\
      bar
 <<<
 <p>foo<br />
-     bar</p>
+bar</p>
 >>> Hard line breaks - 635
 *foo  
 bar*
diff --git a/test/gfm/hard_line_breaks.unit b/test/gfm/hard_line_breaks.unit
index 17c31f0..13e42a5 100644
--- a/test/gfm/hard_line_breaks.unit
+++ b/test/gfm/hard_line_breaks.unit
@@ -21,13 +21,13 @@
      bar
 <<<
 <p>foo<br />
-     bar</p>
+bar</p>
 >>> Hard line breaks - 658
 foo\
      bar
 <<<
 <p>foo<br />
-     bar</p>
+bar</p>
 >>> Hard line breaks - 659
 *foo  
 bar*
diff --git a/tool/common_mark_stats.json b/tool/common_mark_stats.json
index 1248096..46f7044 100644
--- a/tool/common_mark_stats.json
+++ b/tool/common_mark_stats.json
@@ -296,8 +296,8 @@
   "630": "strict",
   "631": "strict",
   "632": "strict",
-  "633": "loose",
-  "634": "loose",
+  "633": "strict",
+  "634": "strict",
   "635": "strict",
   "636": "strict",
   "637": "strict",
diff --git a/tool/common_mark_stats.txt b/tool/common_mark_stats.txt
index 1523784..2a5cc91 100644
--- a/tool/common_mark_stats.txt
+++ b/tool/common_mark_stats.txt
@@ -25,4 +25,4 @@
    3 of    3 – 100.0%  Textual content
   19 of   19 – 100.0%  Thematic breaks
  610 of  649 –  94.0%  TOTAL
- 541 of  610 –  88.7%  TOTAL Strict
+ 543 of  610 –  89.0%  TOTAL Strict
diff --git a/tool/gfm_stats.json b/tool/gfm_stats.json
index 465a830..91699ff 100644
--- a/tool/gfm_stats.json
+++ b/tool/gfm_stats.json
@@ -312,8 +312,8 @@
   "654": "strict",
   "655": "strict",
   "656": "strict",
-  "657": "loose",
-  "658": "loose",
+  "657": "strict",
+  "658": "strict",
   "659": "strict",
   "660": "strict",
   "661": "strict",
diff --git a/tool/gfm_stats.txt b/tool/gfm_stats.txt
index 4e04e48..c1e1819 100644
--- a/tool/gfm_stats.txt
+++ b/tool/gfm_stats.txt
@@ -29,4 +29,4 @@
    3 of    3 – 100.0%  Textual content
   19 of   19 – 100.0%  Thematic breaks
  625 of  671 –  93.1%  TOTAL
- 547 of  625 –  87.5%  TOTAL Strict
+ 549 of  625 –  87.8%  TOTAL Strict