mdbx-tools: добавление опции -f в утилиту mdbx_copy.

src/man1/mdbx_copy.1

@@ -14,6 +14,8 @@ mdbx_copy \- MDBX environment copy tool
 [\c
 .BR \-c ]
 [\c
+.BR \-f ]
+[\c
 .BR \-d ]
 [\c
 .BR \-p ]
@@ -49,6 +51,9 @@ or unused pages will be omitted from the copy. This option will
 slow down the backup process as it is more CPU-intensive.
 Currently it fails if the environment has suffered a page leak.
 .TP
+.BR \-f
+Silently overwrite the target file, if it exists, instead of reaching an error.
+.TP
 .BR \-d
 Alters geometry to enforce the copy to be a dynamic size DB,
 which could be growth and shrink by reasonable steps on the fly.