Use base-compat-batteries-0.12.1+ to provide Solo instances unconditionally #49
Description
Commit d415acf adds TextShow(1) instances for Solo, but only when building against ghc-prim-0.7 or later. Ideally, we would depend on base-compat-batteries-0.12.1 or later to avoid needing this CPP. Let's do so when base-compat-batteries-0.12.1 is widely available in Stackage.