Docs: Misplaced automatic keyword highlighting

[TimoEckstein]

Description of the issue In the documentation, it seems that some keywords are automatically highlighted out of context. This occurs when the code example is not pure python code. Examples are:

• https://quantumai.google/cirq/install, "get" and "base" are highlighted blue

sudo apt-get install texlive-latex-base latexmk

• https://quantumai.google/cirq/dev/development, "from", "last","and" and "for" are highlighted blue

add2virtualenv <paste modules from last command>
./check/pytest [files-and-flags-for-pytest]

Cirq version cirq.master

[TimoEckstein]

xref https://github.com/quantumlib/Cirq/issues/5151