Fix redbiom readthedocs

[charles-cowart]

Related to #2930: The help button on this page (https://qiita.ucsd.edu/redbiom/) links to the following redbiom docs: https://qiita.ucsd.edu/static/doc/html/redbiom.html. The examples given have had their single quotes changed to back-tick and something else. This is will produce an error in Qiita if cut and pasted directly:

soil where ph < 7 and emp_release1 == ‘True’ should be soil where ph < 7 and emp_release1 == 'True'