[hadrian] Fix multiline synopsis rendering
Warming up before ZuriHac :)
Before this patch, Hadrian prints:
/----------------------------------------------------------------------------------------\
| Successfully built library 'ghc-boot-th' (Stage0 InTreeLibs, way v). |
| Library: _build/stage0/libraries/ghc-boot-th/build/libHSghc-boot-th-9.7-inplace.a |
| Library synopsis: Shared functionality between GHC and the @template-haskell@
library. |
\----------------------------------------------------------------------------------------/
After:
/-----------------------------------------------------------------------------------\
| Successfully built library 'ghc-boot-th' (Stage0 InTreeLibs, way v). |
| Library: _build/stage0/libraries/ghc-boot-th/build/libHSghc-boot-th-9.7-inplace.a |
| Library synopsis: Shared functionality between GHC and the @template-haskell@ |
| library. |
\-----------------------------------------------------------------------------------/