"11" and "18" minute reading times now use "an" as they start with a
vowel sound but aren't qualified by "short", "somewhat long", "long", or
"very long". before, it said "a 11 minute read" but now it'll say "an 11
minute read".
Use partialCached to avoid any perf penalty.
TODO: limit the scope I pass to them.
I noticed a teeny tiny perf improvement after doing this, probably
because now some giant data structures only need to be generated once.
