g2h: Escape markdown code blocks that specify a non-word language

This is mostly a workaround for the early version of the file.md which had ```{{

2 files changed, 14 insertions, 0 deletions

diff --git a/src/g2h/file_page.py b/src/g2h/file_page.py
index f2e0550..c317454 100644
--- a/src/g2h/file_page.py
+++ b/src/g2h/file_page.py
@@ -40,6 +40,7 @@ class FilePage(Page):
         if file_type == 'text':
             if self.file_name.lower().endswith('.md'):
                 backtick_max = -1
+                content = re.sub(r'(`{3,}\W)', r'\\\1', content)
             else:
                 matches = re.findall('`+', content)
                 backtick_max = max(max(len(match) for match in matches) if matches else 0, backtick_max)
diff --git a/tests/file_page_test.py b/tests/file_page_test.py
index 5c380b8..63a086a 100644
--- a/tests/file_page_test.py
+++ b/tests/file_page_test.py
@@ -106,3 +106,16 @@ def test_markdown():
     file.data_stream.read.return_value = '```'.encode()
     context = page.context()
     assert(context['backtick_max'] == 0)
+
+def test_markdown_invalid_code_tag():
+    file = MagicMock()
+    tree = MagicMock()
+    commit = MagicMock()
+    commit.hexsha = '123'
+    commit.tree =  tree
+    commit.tree.join.return_value = file
+    page = FilePage('test/file', 'file test', commit, 'file.Md', '', 'file/content')
+    file.data_stream.read.return_value = '```{'.encode()
+    context = page.context()
+    assert(context['backtick_max'] == 0)
+    assert(context['content'] == '\\```{')