fix(codegen/golang): Bring :execlastid in line with the rest (#2378)

Handling it separately is just waiting for bugs to happen. Git-blame
tells me the person to blame is .. me. Whoops.

Author: Jille

internal/codegen/golang/gen.go

@@ -92,7 +92,7 @@ func (t *tmplCtx) codegenQueryRetval(q Query) (string, error) {
 		return "rows, err :=", nil
 	case ":exec":
 		return "_, err :=", nil
-	case ":execrows":
+	case ":execrows", ":execlastid":
 		return "result, err :=", nil
 	case ":execresult":
 		return "return", nil

internal/codegen/golang/templates/stdlib/queryCode.tmpl

@@ -87,18 +87,8 @@ func (q *Queries) {{.MethodName}}(ctx context.Context, {{ dbarg }} {{.Arg.Pair}}
 {{if eq .Cmd ":execlastid"}}
 {{range .Comments}}//{{.}}
 {{end -}}
-{{- if $.EmitMethodsWithDBArgument -}}
-func (q *Queries) {{.MethodName}}(ctx context.Context, db DBTX, {{.Arg.Pair}}) (int64, error) {
-{{- else -}}
-func (q *Queries) {{.MethodName}}(ctx context.Context, {{.Arg.Pair}}) (int64, error) {
-{{- end -}}
-    {{- if $.EmitPreparedQueries}}
-    result, err := q.exec(ctx, q.{{.FieldName}}, {{.ConstantName}}, {{.Arg.Params}})
-    {{- else if $.EmitMethodsWithDBArgument}}
-    result, err := db.ExecContext(ctx, {{.ConstantName}}, {{.Arg.Params}})
-    {{- else}}
-    result, err := q.db.ExecContext(ctx, {{.ConstantName}}, {{.Arg.Params}})
-    {{- end}}
+func (q *Queries) {{.MethodName}}(ctx context.Context, {{ dbarg }} {{.Arg.Pair}}) (int64, error) {
+    {{- template "queryCodeStdExec" . }}
     if err != nil {
         return 0, err
     }