Merge 79512c9fd8 into 54a8f0ce21

Fix regression in content summarization so that we can use empty
summary by using the manual summary divider. Since v0.123, there
has been the regression that causes Hugo to use automatic summary
generation when the manual summary results in an empty string,
even if there is a `<!--more-->` summary divider.

hugolib/page__content.go

@@ -770,7 +770,7 @@ func (c *cachedContent) contentPlain(ctx context.Context, cp *pageContentOutput)
 			result.readingTime = (result.wordCount + 212) / 213
 		}
 
-		if rendered.summary != "" {
+		if c.pi.hasSummaryDivider || rendered.summary != "" {
 			result.summary = rendered.summary
 			result.summaryTruncated = rendered.summaryTruncated
 		} else if cp.po.p.m.pageConfig.Summary != "" {