sysutils/lnav: Fix distinfo
Distinfo was wrongly updated to that of BETA1 release when this port
was updated to 0.10.1.
While I'm here,
- Switch to DISTVERSION
- Re-format Makefile with portfmt
PR: 259560
Fixes: fb07233b044e (sysutils/lnav: Update to 0.10.1)