small fix

source/02-baryon.md

@@ -16,12 +16,15 @@ $$
 **Based on Euclidean notation (not the same as the $\gamma_5$ notation used in the code).**
 
 The first baryon interpolation operator for proton is:
+
 $$
 \begin{align}
 N_i(x) =& \epsilon_{a,b,c} u_{i,a}(x) \big( u_{j,b}(x) (C\gamma_5)_{j,k} d_{k,c}\big)
 \end{align}
 $$
+
 where summing over repeated indices is assumed, where
+
 $$
 \begin{align}
 C =& \gamma_t \gamma_y =