docs: extend the dump-header documentation

This commit extends the documentation of the --dump-header command-line
option to reflect the behavior introduced in 8b1e5df7.

See #10079
Closes #10085

diff --git a/docs/cmdline-opts/dump-header.d b/docs/cmdline-opts/dump-header.d
index 3dabac85e65c17f54025032cf8fad8d559751894..3e39f600733115a1ad1ca78aefab8bfe4005fb9b 100644 (file)
--- a/docs/cmdline-opts/dump-header.d
+++ b/docs/cmdline-opts/dump-header.d
@@ -16,3 +16,6 @@ received, the use of this option will create an empty file.
 
 When used in FTP, the FTP server response lines are considered being "headers"
 and thus are saved there.
+
+Having multiple transfers in one set of operations (i.e. the URLs in one
+--next clause), will append them to the same file, seperated by a blank line.