Skip precompiling imports for Go Build

`gnopls` run diagnostics on Open and Save. Diagnostics uses
`gno precompile --gobuild` to get go build error. This command
precompile imports automatically unless used with flag
`-skip-imports`. It makes working dir dirty by generating
`*.gno.gen.go` files. So using it with flag `-skip-imports`.

internal/tools/build.go

@@ -8,5 +8,5 @@ import (
 // Build a Gno package: gno precompile -gobuild <dir>.
 // TODO: Remove this in the favour of directly using tools/precompile.go
 func Build(rootDir string) ([]byte, error) {
-	return exec.Command("gno", "precompile", "-gobuild", filepath.Join(rootDir)).CombinedOutput()
+	return exec.Command("gno", "precompile", "-skip-imports", "-gobuild", filepath.Join(rootDir)).CombinedOutput()
 }