fix index

Author: CarloLucibello

docs/src/api/basic.md

@@ -9,7 +9,7 @@ CurrentModule = GraphNeuralNetworks
 ```@index
 Order = [:type, :function]
 Modules = [GraphNeuralNetworks]
-Pages = ["api/basics.md"]
+Pages = ["basic.md"]
 ```
 
 ## Docs

docs/src/api/conv.md

@@ -8,7 +8,7 @@ CurrentModule = GraphNeuralNetworks
 
 ```@index
 Order = [:type, :function]
-Pages   = ["conv.md"]
+Pages = ["conv.md"]
 ```
 
 ## Docs

docs/src/api/gnngraph.md

@@ -10,7 +10,7 @@ Documentation page for the graph type `GNNGraph` provided GraphNeuralNetworks.jl
 
 ```@index
 Order = [:type, :function]
-Pages   = ["graphs.md"]
+Pages   = ["gnngraph.md"]
 ```
 
 ## Docs