Fix bad missing-references.json due to PR merge race condition.

aka some missing references were fixed between the last build of the
nitpicky-mode PR and its merge.

Author: anntzer

doc/missing-references.json

@@ -5730,4 +5730,4 @@
       "doc/users/prev_whats_new/whats_new_1.5.rst:737"
     ]
   }
-}
+}

tutorials/introductory/usage.py

@@ -496,9 +496,9 @@ def my_plotter(ax, data1, data2, param_dict):
 # Using non-builtin backends
 # --------------------------
 # More generally, any importable backend can be selected by using any of the
-# methods above. If `name.of.the.backend` is the module containing the backend,
-# use `module://name.of.the.backend` as the backend name, e.g.
-# `matplotlib.use('module://name.of.the.backend')`.
+# methods above. If ``name.of.the.backend`` is the module containing the
+# backend, use ``module://name.of.the.backend`` as the backend name, e.g.
+# ``matplotlib.use('module://name.of.the.backend')``.
 #
 #
 # .. _interactive-mode: