Fix an error for invalid TeX

Author: nono

lib/html/pipeline/svgtex.rb

@@ -89,8 +89,6 @@ def call
             rsp = session.post(context[:svgtex_url], :q => eqn)
             if rsp.status == 200
               node.replace "<img style='display: inline; max-height: 1em;' class='mathjax' src='data:image/svg+xml;base64,#{Base64.encode64 rsp.body}' alt='#{CGI.escape_html eqn}' />"
-            else
-              node.inner_text = eqn
             end
           end
           doc