Kindsys: Replace "Declaration" with "Definition" (#62515)

* s/Declaration/Definition/g

* s/DeclForGen/DefForGen/g

* Rename some local vars

pkg/codegen/generators.go

@@ -10,44 +10,45 @@ import (
 	"github.com/grafana/thema"
 )
 
-type OneToOne codejen.OneToOne[*DeclForGen]
-type OneToMany codejen.OneToMany[*DeclForGen]
-type ManyToOne codejen.ManyToOne[*DeclForGen]
-type ManyToMany codejen.ManyToMany[*DeclForGen]
+type OneToOne codejen.OneToOne[*DefForGen]
+type OneToMany codejen.OneToMany[*DefForGen]
+type ManyToOne codejen.ManyToOne[*DefForGen]
+type ManyToMany codejen.ManyToMany[*DefForGen]
 
-// ForGen is a codejen input transformer that converts a pure kindsys.SomeDecl into
-// a DeclForGen by binding its contained lineage.
-func ForGen(rt *thema.Runtime, decl kindsys.SomeDecl) (*DeclForGen, error) {
-	lin, err := decl.BindKindLineage(rt)
+// ForGen is a codejen input transformer that converts a pure kindsys.SomeDef into
+// a DefForGen by binding its contained lineage.
+func ForGen(rt *thema.Runtime, def kindsys.SomeDef) (*DefForGen, error) {
+	lin, err := def.BindKindLineage(rt)
 	if err != nil {
 		return nil, err
 	}
 
-	return &DeclForGen{
-		SomeDecl: decl,
-		lin:      lin,
+	return &DefForGen{
+		SomeDef: def,
+		lin:     lin,
 	}, nil
 }
 
-// DeclForGen wraps [kindsys.SomeDecl] to provide trivial caching of
+// DefForGen wraps [kindsys.SomeDef] to provide trivial caching of
 // the lineage declared by the kind (nil for raw kinds).
-type DeclForGen struct {
-	kindsys.SomeDecl
+// TODO this type is unneeded - kindsys.Kind is sufficient.
+type DefForGen struct {
+	kindsys.SomeDef
 	lin thema.Lineage
 }
 
-// Lineage returns the [thema.Lineage] for the underlying [kindsys.SomeDecl].
-func (decl *DeclForGen) Lineage() thema.Lineage {
-	return decl.lin
+// Lineage returns the [thema.Lineage] for the underlying [kindsys.SomeDef].
+func (def *DefForGen) Lineage() thema.Lineage {
+	return def.lin
 }
 
 // ForLatestSchema returns a [SchemaForGen] for the latest schema in this
-// DeclForGen's lineage.
-func (decl *DeclForGen) ForLatestSchema() SchemaForGen {
-	comm := decl.Properties.Common()
+// DefForGen's lineage.
+func (def *DefForGen) ForLatestSchema() SchemaForGen {
+	comm := def.Properties.Common()
 	return SchemaForGen{
 		Name:    comm.Name,
-		Schema:  decl.Lineage().Latest(),
+		Schema:  def.Lineage().Latest(),
 		IsGroup: comm.LineageIsGroup,
 	}
 }