Merge branch 'ghc-8.6' into ghc-8.8

CHANGES.md

README.md

doc/invoking.rst

ghc.mk

haddock-api/haddock-api.cabal

haddock-api/resources/html/Linuwial.std-theme/linuwial.css

haddock-api/resources/html/Linuwial.std-theme/synopsis.png

haddock-api/resources/html/README.md

haddock-api/resources/html/haddock-bundle.min.js

haddock-api/resources/html/js-src/details-helper.ts

haddock-api/resources/html/js-src/details-helper.tsx

haddock-api/resources/html/js-src/init.ts

haddock-api/resources/html/js-src/style-menu.tsx

haddock-api/resources/html/quick-jump.css

haddock-api/src/Haddock.hs

haddock-api/src/Haddock/Backends/Hoogle.hs

haddock-api/src/Haddock/Backends/LaTeX.hs

haddock-api/src/Haddock/Backends/Xhtml/Decl.hs

haddock-api/src/Haddock/Backends/Xhtml/Themes.hs

haddock-api/src/Haddock/GhcUtils.hs