lib: let the max filesize option stop too big transfers too

Previously it would only stop them from getting started if the size is
known to be too big then.

Update the libcurl and curl docs accordingly.

Fixes #11810
Reported-by: Elliot Killick
Assisted-by: Jay Satiro
Closes #11820

docs/cmdline-opts/max-filesize.d

@@ -18,6 +18,9 @@ A size modifier may be used. For example, Appending 'k' or 'K' counts the
 number as kilobytes, 'm' or 'M' makes it megabytes, while 'g' or 'G' makes it
 gigabytes. Examples: 200K, 3m and 1G. (Added in 7.58.0)
 
-**NOTE**: The file size is not always known prior to download, and for such
-files this option has no effect even if the file transfer ends up being larger
-than this given limit.
+**NOTE**: before curl 8.4.0, when the file size is not known prior to
+download, for such files this option has no effect even if the file transfer
+ends up being larger than this given limit.
+
+Starting with curl 8.4.0, this option aborts the transfer if it reaches the
+threshold during transfer.

docs/libcurl/opts/CURLOPT_MAXFILESIZE.3

@@ -41,6 +41,9 @@ transfers this option has no effect - even if the file transfer eventually
 ends up being larger than this given limit.
 
 If you want a limit above 2GB, use \fICURLOPT_MAXFILESIZE_LARGE(3)\fP.
+
+Since 8.4.0, this option also stops ongoing transfers if they reach this
+threshold.
 .SH DEFAULT
 None
 .SH PROTOCOLS

docs/libcurl/opts/CURLOPT_MAXFILESIZE_LARGE.3

@@ -40,6 +40,9 @@ returned.
 The file size is not always known prior to the download start, and for such
 transfers this option has no effect - even if the file transfer eventually
 ends up being larger than this given limit.
+
+Since 8.4.0, this option also stops ongoing transfers if they reach this
+threshold.
 .SH DEFAULT
 None
 .SH PROTOCOLS