RST rendering: case where preview does not display code-block sections

[wesinator]

https://github.com/ThreatConnect-Inc/tcex/blob/master/docs/src/module_ti.rst

code-block such as the one at line 261 are not rendered in the Github preview for this rst file.

I think this is a regression, unless there is something weird about that rst. The docs render correctly - https://threatconnect-inc.github.io/tcex/module_ti.html#create-an-indicator

[wesinator]

Another case https://github.com/VirusTotal/yara/blob/60b1b4d4e613916350b2bfd43752a042432d94da/docs/yarapython.rst

code block at line 88 is not rendered in Github rst preview