Prepare release 1.9.0.0

ChangeLog.md

ghcide-bench/ghcide-bench.cabal

ghcide/ghcide.cabal

ghcide/test/ghcide-test-utils.cabal

haskell-language-server.cabal

hie-compat/hie-compat.cabal

hls-graph/hls-graph.cabal

hls-plugin-api/hls-plugin-api.cabal

hls-test-utils/hls-test-utils.cabal

...er-format-plugin/hls-alternate-number-format-plugin.cabal

plugins/hls-brittany-plugin/hls-brittany-plugin.cabal

plugins/hls-cabal-fmt-plugin/hls-cabal-fmt-plugin.cabal

plugins/hls-cabal-plugin/hls-cabal-plugin.cabal

...hls-call-hierarchy-plugin/hls-call-hierarchy-plugin.cabal

...e-signature-plugin/hls-change-type-signature-plugin.cabal

plugins/hls-class-plugin/hls-class-plugin.cabal

plugins/hls-code-range-plugin/hls-code-range-plugin.cabal

plugins/hls-eval-plugin/hls-eval-plugin.cabal

...s-explicit-fixity-plugin/hls-explicit-fixity-plugin.cabal

...explicit-imports-plugin/hls-explicit-imports-plugin.cabal