The namespaces used by "log --decorate" from "refs/" hierarchy by
default has been tightened.
* ds/decorate-filter-tweak:
fetch: use ref_namespaces during prefetch
maintenance: stop writing log.excludeDecoration
log: create log.initialDecorationSet=all
log: add --clear-decorations option
log: add default decoration filter
log-tree: use ref_namespaces instead of if/else-if
refs: use ref_namespaces for replace refs base
refs: add array of ref namespaces
t4207: test coloring of grafted decorations
t4207: modernize test
refs: allow "HEAD" as decoration filter
c068a3b8ee