codegen: make generated godoc more relevant for without-rowid tables

doc/TODO.txt

@@ -22,8 +22,6 @@ TODO: codegen SaveXyz update path doesn't check foreign keys
 - Insert path has FK error handling, but the update path wraps everything in Must
 - An update that violates an FK constraint will panic instead of returning an error
 
-TODO: codegen `without rowid` tables properly
-
 TODO: generated test file inclues global test DB setup, which is wrong
 
 TODO: join-tables

doc/links.txt

@@ -1 +1,3 @@
 https://astexplorer.net/
+https://github.com/dave/dst
+https://disaev.me/p/writing-useful-go-analysis-linter/

pkg/codegen/modelgenerate/generate_model.go

@@ -515,11 +515,16 @@ func GenerateSaveItemFunc(tbl schema.Table) *ast.FuncDecl {
 		}(),
 	}
 
+	docLines := []*ast.Comment{
+		{Text: fmt.Sprintf("// Save%s creates or updates a %s in the database.", tbl.GoTypeName, tbl.GoTypeName)},
+	}
+	if tbl.IsWithoutRowid {
+		docLines = append(docLines, &ast.Comment{Text: "// If a row with the same key already exists, it will be updated; otherwise it will be created."})
+	} else {
+		docLines = append(docLines, &ast.Comment{Text: "// If the item doesn't exist (has no ID set), it will create it; otherwise it will do an update."})
+	}
 	funcDecl := &ast.FuncDecl{
-		Doc: &ast.CommentGroup{List: []*ast.Comment{
+		Doc:  &ast.CommentGroup{List: docLines},
-			{Text: fmt.Sprintf("// Save%s creates or updates a %s in the database.", tbl.GoTypeName, tbl.GoTypeName)},
-			{Text: "// If the item doesn't exist (has no ID set), it will create it; otherwise it will do an update."},
-		}},
 		Recv: dbRecv,
 		Name: ast.NewIdent("Save" + tbl.GoTypeName),
 		Type: &ast.FuncType{