* origin/newspeak:
comments: replace "partition" with "shard"
t/xcpdb-reshard: use 'shard' term in local variables
xapcmd: favor 'shard' over 'part' in local variables
search: use "shard" for local variable
v2writable: use "epoch" consistently when referring to git repos
adminedit: "part" => "shard" for local variables
v2writable: rename local vars to match Xapian terminology
v2writable: avoid "part" in internal subs and fields
search*: rename {partition} => {shard}
xapcmd: update comments referencing "partitions"
v2: rename SearchIdxPart => SearchIdxShard
inboxwritable: s/partitions/shards/ in local var
tests: change messages to use "shard" instead of partition
v2writable: rename {partitions} field to {shards}
v2writable: count_partitions => count_shards
searchidxpart: start using "shard" in user-visible places
rename reference to git epochs as "partitions"
admin|xapcmd: user-facing messages say "shard"
v2writable: update comments regarding xcpdb --reshard
doc: rename our Xapian "partitions" to "shards"