Do the same doc improvements to --follow-metalink

doc/manual-src/en/aria2c.rst

@@ -848,7 +848,9 @@ Metalink Specific Options
   file and downloads files mentioned in it.
   If ``mem`` is specified, a metalink file is not written to the disk, but is just
   kept in memory.
-  If ``false`` is specified, the action mentioned above is not taken.
+  If ``false`` is specified, the ``.metalink`` file is downloaded to
+  the disk, but is not parsed as a metalink file and its contents are not
+  downloaded.
   Default: ``true``
 
 .. option:: --metalink-base-uri=<URI>

src/usage_text.h

@@ -388,8 +388,10 @@
     "                              mentioned in it.\n"                  \
     "                              If mem is specified, a metalink file is not\n" \
     "                              written to the disk, but is just kept in memory.\n" \
-    "                              If false is specified, the action mentioned above\n" \
-    "                              is not taken.")
+    "                              If false is specified, the .metalink file is\n" \
+    "                              downloaded to the disk, but is not parsed as a\n" \
+    "                              metalink file and its contents are not\n" \
+    "                              downloaded.")
 #define TEXT_METALINK_ENABLE_UNIQUE_PROTOCOL                            \
   _(" --metalink-enable-unique-protocol[=true|false] If true is given and several\n" \
     "                              protocols are available for a mirror in a metalink\n" \