internal: move PackageMeta to unit.go

No code changes are made - only code in motion.

For golang/go#39629

Change-Id: I287f8628ca00c0fe3819912dcc77d1b90bd713f6
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/252920
Reviewed-by: Jonathan Amsterdam <[email protected]>

Author: julieqiu

internal/discovery.go

@@ -103,15 +103,6 @@ type Module struct {
 	LegacyPackages []*LegacyPackage
 }
 
-// PackageMeta represents the metadata of a package in a module version.
-type PackageMeta struct {
-	Path              string
-	Name              string
-	Synopsis          string
-	IsRedistributable bool
-	Licenses          []*licenses.Metadata // metadata of applicable licenses
-}
-
 // IndexVersion holds the version information returned by the module index.
 type IndexVersion struct {
 	Path      string

internal/unit.go

@@ -69,6 +69,15 @@ type Readme struct {
 	Contents string
 }
 
+// PackageMeta represents the metadata of a package in a module version.
+type PackageMeta struct {
+	Path              string
+	Name              string
+	Synopsis          string
+	IsRedistributable bool
+	Licenses          []*licenses.Metadata // metadata of applicable licenses
+}
+
 // A FieldSet is a bit set of struct fields. It is used to avoid reading large
 // struct fields from the data store. FieldSet is also the type of the
 // individual bit values. (Think of them as singleton sets.)