Document pwd as an sftp quote command for curl(1), and show it as

lower case for consistency since sftp commands are case insensitive.

docs/curl.1

@@ -909,7 +909,7 @@ the server returns failure for one of the commands, the entire operation
 will be aborted. You must send syntactically correct FTP commands as
 RFC959 defines to FTP servers, or one of the following commands (with
 appropriate arguments) to SFTP servers: chgrp, chmod, chown, ln, mkdir,
-rename, rm, rmdir, symlink.
+pwd, rename, rm, rmdir, symlink.
 
 This option can be used multiple times.
 .IP "--random-file <file>"

docs/libcurl/curl_easy_setopt.3

@@ -847,8 +847,8 @@ properly filled in with text strings. Use \fIcurl_slist_append(3)\fP
 to append strings (commands) to the list, and clear the entire list
 afterwards with \fIcurl_slist_free_all(3)\fP. Disable this operation
 again by setting a NULL to this option.
-The valid SFTP commands are: chgrp, chmod, chown, ln, mkdir,
-rename, rm, rmdir, symlink, PWD. (SFTP support added in 7.16.3)
+The valid SFTP commands are: chgrp, chmod, chown, ln, mkdir, pwd,
+rename, rm, rmdir, symlink. (SFTP support added in 7.16.3)
 .IP CURLOPT_POSTQUOTE
 Pass a pointer to a linked list of FTP or SFTP commands to pass to the
 server after your ftp transfer request. The linked list should be a