Add some line breaks to urbs' math code

Makes it more readable. Case in point: I now see that the double
backslashes signifying line breaks are missing. But I'll fix that in the
next commit.

doc/source/frameworks/technologies.rst

@@ -177,9 +177,12 @@ urbs
 
 .. math::
 
-    &\epsilon^{\text{in}}_{y,g,d,t}=r^{\text{in}}_{y,g,d}\tau_{y,g,t} \forall y\in Y,\forall g\in G,~d\in D,~t \in T_m
-    &\epsilon^{\text{out}}_{y,g,d,t}=r^{\text{out}}_{y,g,d}\tau_{y,g,t} \forall y\in Y\forall g\in G,~d\in D,~t \in T_m
-    &\tau_{y,g,t}\leq \kappa_{y,g} \forall y\in y\forall g\in G,~d\in D,~t \in T_m
+    &\epsilon^{\text{in}}_{y,g,d,t}=r^{\text{in}}_{y,g,d}\tau_{y,g,t}
+    \forall y\in Y,\forall g\in G,~d\in D,~t \in T_m
+    &\epsilon^{\text{out}}_{y,g,d,t}=r^{\text{out}}_{y,g,d}\tau_{y,g,t}
+    \forall y\in Y\forall g\in G,~d\in D,~t \in T_m
+    &\tau_{y,g,t}\leq \kappa_{y,g}
+    \forall y\in y\forall g\in G,~d\in D,~t \in T_m
 
 Storages
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