Update documentation.

Author: samuelsonric

docs/src/solvers/solvers.md

@@ -177,6 +177,16 @@ UMFPACKFactorization
 SparspakFactorization
 ```
 
+### CliqueTrees.jl
+
+!!! note
+    
+    Using this solver requires adding the package CliqueTrees.jl, i.e. `using CliqueTrees`
+
+```@docs
+CliqueTreesFactorization
+```
+
 ### Krylov.jl
 
 ```@docs

src/factorization.jl

@@ -1166,6 +1166,10 @@ end
         snd = CliqueTrees.DEFAULT_SUPERNODE_TYPE,
         reuse_symbolic = true,
     )
+
+The sparse Cholesky factorization algorithm implemented in CliqueTrees.jl.
+The implementation is pure-Julia and accepts arbitrary numeric types. It is
+somewhat slower than CHOLMOD.
 """
 struct CliqueTreesFactorization{A, S} <: AbstractSparseFactorization
     alg::A