markdown: fixed hr styling, and strong style.

rhodecode/public/css/legacy_code_styles.less

@@ -165,6 +165,7 b' div.markdown-block h6 {'
 div.markdown-block hr {
     border: 0;
     color: #e6e5e5;
+    background-color: #e6e5e5;
     height: 3px;
     margin-bottom: 13px;
 }
@@ -200,6 +201,12 b' div.markdown-block img {'
   background-color: #fff;
 }
 
+
+div.markdown-block strong {
+  font-weight: 600;
+  margin: 0;
+}
+
 div.markdown-block ul,
 div.markdown-block ol {
     padding-left: 30px !important;