fix typos in docs

docs/source/interactions.ipynb

@@ -500,7 +500,7 @@
     "MES^i_m = 2\\cdot\\frac{P^i_m\\cdot C^i_m}{P^i_m + C^i_m}\n",
     "$$\n",
     "\n",
-    "This can be interpreted as a normalized number of all observed metabolic interactions (becuse $P\\cdot C) is the number of all possible directed combinations of producers and consumers. So it is a measure of cross-feeding. \n",
+    "This can be interpreted as a normalized number of all observed metabolic interactions (becuse $P\\cdot C$ is the number of all possible directed combinations of producers and consumers). So it is a measure of cross-feeding. \n",
     "\n",
     "It can also be calculated very fast for large data sets, so let's go."
    ]