fix: explicit undefined check in header transclude

Jacky Zhao

2023-11-19 516d9a27e7e2c08efdf24857b03f1831dbaf7da7

 quartz/processors/filter.ts

@@ -1,5 +1,5 @@
import { BuildCtx } from "../ctx"
import { PerfTimer } from "../perf"
import { BuildCtx } from "../util/ctx"
import { PerfTimer } from "../util/perf"
import { ProcessedContent } from "../plugins/vfile"

export function filterContent(ctx: BuildCtx, content: ProcessedContent[]): ProcessedContent[] {