Merge `GHC.Maybe` into `GHC.Base` #104

Job	Run time
pre_check	7s
Installing Coq dependencies (ubuntu-latest, 4.07.1, 8.10.2)	28s
Cross building hs-to-coq with multiple GHC versions (ubuntu-latest, 8.4.3, lts-12.26)	1m 31s
Installing Haskell dependencies (ubuntu-latest, 8.4.3, lts-12.0)	34s
Cross building hs-to-coq with multiple GHC versions (ubuntu-latest, 8.4.3, lts-14.27)	1m 29s
Cross building hs-to-coq with multiple GHC versions (ubuntu-latest, 8.4.3, lts-16.31)	13m 35s
Cross building hs-to-coq with multiple GHC versions (ubuntu-latest, 8.4.3, lts-18.10)	1m 25s
Testing base, containers, transformers, GHC, etc. (ubuntu-latest, 4.07.1, 8.10.2)	6h 0m 13s
Tests, base tests, and other examples (ubuntu-latest, 8.4.3, lts-12.0, 4.07.1, 8.10.2)	6h 0m 13s
Translation (ensures convenience copy is up-to-date) (ubuntu-latest, 8.4.3, lts-12.0, 4.07.1, 8.1...	6m 45s
Testing containers extraction (ubuntu-latest, 8.4.3, lts-12.0, 4.07.1, 8.10.2)	6h 0m 13s
	18h 26m 33s

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