Fix export warning

YingboMa · ararslan · YingboMa · commit b2ca8735064d · 2022-07-12T20:45:24.000-04:00
Co-authored-by: Alex Arslan &lt;ararslan@comcast.net&gt;
diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
@@ -41,6 +41,7 @@ import SymbolicUtils.Rewriters: Chain, Postwalk, Prewalk, Fixpoint
 import JuliaFormatter
 
 using Reexport
+using Symbolics: degree
 @reexport using Symbolics
 export @derivatives
 using Symbolics: _parse_vars, value, @derivatives, get_variables,
