Tighten lnw comments and log form after review (#87)

Cross-reference lnwChapterRe from the function doc instead of restating
its rationale, drop the redundant '; skipping' from the fail-closed log
to match the package's bare verb:detail form, and reword the truncation
comment so the logged body length is not described as a code-made
distinction.

backend/internal/latest/sites_test.go

@@ -414,8 +414,8 @@ func TestLatestChapterFrom(t *testing.T) {
 		// Stored before the slug split, so the address carries the ...-not
 		// Chapter Slug; the 100-423 block under the other slug must still win.
 		// The body is the chapter-list portion of lnwSeriesFixture with the
-		// comment block omitted (that is the next case's job); the marker is
-		// kept, because a body without it is skipped, not scanned.
+		// comment block omitted; the marker is kept, because a body without it
+		// is skipped, not scanned.
 		{
 			name:      "lightnovelworld max spans both chapter slugs",
 			site:      "lightnovelworld",