chore: drop unused import

I didn't even know one could import modules from executables! Not sure how to feel about that.

lakefile.lean

@@ -1,5 +1,4 @@
 import Lake
-import Lake.CLI.Main
 open System Lake DSL
 
 package «doc-gen4»
@@ -114,4 +113,4 @@ library_facet docs (lib) : FilePath := do
         let traces ← staticFiles.mapM computeTrace
         let indexTrace := mixTraceArray traces
 
-        return (dataFile, trace.mix indexTrace)
+        return (dataFile, trace.mix indexTrace)