Point to Symbolics.jl

This should help guide people in the right direction.

Author: ChrisRackauckas

README.md

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-SymbolicUtils.jl provides various utilities for symbolic computing.
+SymbolicUtils.jl provides various utilities for symbolic computing. SymbolicUtils.jl is what one would use to build
+a Computer Algebra System (CAS). If you're looking for a complete CAS, similar to SymPy or Mathematica, see
+[Symbolics.jl](https://github.com/JuliaSymbolics/Symbolics.jl). If you want to build a crazy CAS for your weird
+Octonian algebras, you've come to the right place.
 
 [Symbols in SymbolicUtils](https://juliasymbolics.github.io/SymbolicUtils.jl/#creating_symbolic_expressions) carry type information. Operations on them propagate this information. [A rule-based rewriting language](https://juliasymbolics.github.io/SymbolicUtils.jl/#rule-based_rewriting) can be used to find subexpressions that satisfy arbitrary conditions and apply arbitrary transformations on the matches. The library also contains a set of useful [simplification](https://juliasymbolics.github.io/SymbolicUtils.jl/#simplification) rules for expressions of numeric symbols and numbers. These can be remixed and extended for special purposes.