cue/load: deduplicate underscore import of ./pkg

Spotted in passing. Harmless, but also unnecessary.
Move it to doc.go near the package documentation, which is the closest
to a top-level file we have for this package.

While here, remove an unnecessary newline in pkg/register.go.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I59bca21889158b231600bd1326752abb8fed0262
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1201389
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Roger Peppe <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

cue/load/doc.go

@@ -14,3 +14,9 @@
 
 // Package load loads CUE instances.
 package load
+
+// Trigger the unconditional loading of all core builtin packages if load is used.
+// This was deemed the simplest way to avoid having to import this line explicitly,
+// and thus breaking existing code, for the majority of cases,
+// while not introducing an import cycle.
+import _ "cuelang.org/go/pkg"

cue/load/instances.go

@@ -30,12 +30,6 @@ import (
 	"cuelang.org/go/internal/mod/modpkgload"
 	"cuelang.org/go/internal/mod/modrequirements"
 	"cuelang.org/go/mod/module"
-
-	// Trigger the unconditional loading of all core builtin packages if load
-	// is used. This was deemed the simplest way to avoid having to import
-	// this line explicitly, and thus breaking existing code, for the majority
-	// of cases, while not introducing an import cycle.
-	_ "cuelang.org/go/pkg"
 )
 
 // Instances returns the instances named by the command line arguments 'args'.

cue/load/loader.go

@@ -26,12 +26,6 @@ import (
 	"cuelang.org/go/cue/errors"
 	"cuelang.org/go/cue/token"
 	"cuelang.org/go/internal/mod/modpkgload"
-
-	// Trigger the unconditional loading of all core builtin packages if load
-	// is used. This was deemed the simplest way to avoid having to import
-	// this line explicitly, and thus breaking existing code, for the majority
-	// of cases, while not introducing an import cycle.
-	_ "cuelang.org/go/pkg"
 )
 
 type loader struct {

pkg/register.go

@@ -27,7 +27,6 @@ import (
 	_ "cuelang.org/go/pkg/encoding/json"
 	_ "cuelang.org/go/pkg/encoding/yaml"
 	_ "cuelang.org/go/pkg/html"
-
 	_ "cuelang.org/go/pkg/list"
 	_ "cuelang.org/go/pkg/math"
 	_ "cuelang.org/go/pkg/math/bits"