Seed directory renamed to "..-seed".

The prior name, "!!-seed", clearly conflicted with essential constraints under
zsh itself (e.g., the history mechanism) and filesystems for an erstwhile-
operating-system-in-unsurprising-decline-whose-name-shall-remain-nameless-if-
not-blameless-but-whose-filesystems-shall-be-named (e.g., FAT, NTFS).