in inline contexts, resolve <br/> to a space instead of an empty string (#202)

Signed-off-by: chrispy <chrispy@synopsys.com>

tests/test_conversions.py

@@ -79,6 +79,8 @@ def test_blockquote_nested():
 def test_br():
     assert md('a<br />b<br />c') == 'a  \nb  \nc'
     assert md('a<br />b<br />c', newline_style=BACKSLASH) == 'a\\\nb\\\nc'
+    assert md('<h1>foo<br />bar</h1>', heading_style=ATX) == '\n\n# foo bar\n\n'
+    assert md('<td>foo<br />bar</td>', heading_style=ATX) == ' foo bar |'
 
 
 def test_code():