add sources to docs project

Author: asinghvi17

docs/Project.toml

@@ -15,7 +15,7 @@ SymbolicIndexingInterface = "2efcf032-c050-4f8e-a9bb-153293bab1f5"
 [compat]
 Documenter = "1.3"
 Lux = "1"
-ModelingToolkit = "9.9"
+ModelingToolkit = "9"
 ModelingToolkitNeuralNets = "1"
 ModelingToolkitStandardLibrary = "2.7"
 Optimization = "3.24, 4.0"
@@ -25,3 +25,6 @@ Plots = "1"
 SciMLStructures = "1.1.0"
 StableRNGs = "1"
 SymbolicIndexingInterface = "0.3.15"
+
+[sources]
+ModelingToolkitNeuralNets = { path = ".." }