Rename rv_formal.cabal to rvFormal

It appears that the convention is to use the package name as the
filename

```
error: path '/nix/store/3bljihq1ighvsr9ghaw5fvflcdapsrff-haskell-project-plan-to-nix-pkgs/.plan.nix/rvFormal.nix' does not exist
```

rvFormal.cabal

@@ -0,0 +1,139 @@
+cabal-version:       2.4
+name:                rvFormal
+version:             0.1
+license:             BSD-2-Clause
+author:              John Smith <john@example.com>
+maintainer:          John Smith <john@example.com>
+
+common common-options
+  default-extensions:
+    NumericUnderscores
+    DeriveDataTypeable
+    BangPatterns
+    BinaryLiterals
+    ConstraintKinds
+    DataKinds
+    DefaultSignatures
+    DeriveAnyClass
+    DeriveDataTypeable
+    DeriveFoldable
+    DeriveFunctor
+    DeriveGeneric
+    DeriveLift
+    DeriveTraversable
+    DerivingStrategies
+    InstanceSigs
+    KindSignatures
+    LambdaCase
+    NoStarIsType
+    PolyKinds
+    RankNTypes
+    ScopedTypeVariables
+    StandaloneDeriving
+    TupleSections
+    TypeApplications
+    TypeFamilies
+    TypeOperators
+    ViewPatterns
+    FlexibleContexts
+    MagicHash
+
+    -- TemplateHaskell is used to support convenience functions such as
+    -- 'listToVecTH' and 'bLit'.
+    TemplateHaskell
+    QuasiQuotes
+
+    -- Prelude isn't imported by default as Clash offers Clash.Prelude
+    NoImplicitPrelude
+  ghc-options:
+    -Wall -Wcompat
+    -haddock
+
+    -- Plugins to support type-level constraint solving on naturals
+    -fplugin GHC.TypeLits.Extra.Solver
+    -fplugin GHC.TypeLits.Normalise
+    -fplugin GHC.TypeLits.KnownNat.Solver
+
+    -- Clash needs access to the source code in compiled modules
+    -fexpose-all-unfoldings
+
+    -- Worker wrappers introduce unstable names for functions that might have
+    -- blackboxes attached for them. You can disable this, but be sure to add
+    -- a no-specialize pragma to every function with a blackbox.
+    -fno-worker-wrapper
+  build-depends:
+    base,
+    Cabal,
+
+    -- clash-prelude will set suitable version bounds for the plugins
+    clash-prelude >= 1.6.4 && < 1.10,
+    ghc-typelits-natnormalise,
+    ghc-typelits-extra,
+    ghc-typelits-knownnat,
+    binary,
+    bytestring,
+    mtl,
+    pretty-show
+
+custom-setup
+  setup-depends:
+    base          >= 4.11,
+    Cabal         >= 2.4,
+    cabal-doctest >= 1.0.1 && <1.1
+
+library
+  import: common-options
+  hs-source-dirs: hs
+  exposed-modules:
+    Simulation
+  other-modules:
+    Fetch,
+    Decode,
+    DecodeTypes,
+    Execute,
+    Read,
+    Peripherals.Ram,
+    Peripherals.Uart,
+    Peripherals.UartCFFI,
+    Peripherals.Setup,
+    Peripherals.Teardown,
+    Types,
+    Bus,
+    BusTypes,
+    Cpu,
+    RegFiles,
+    Exceptions,
+    Util
+  c-sources: c/uart_sim_device.c
+  include-dirs: c
+  default-language: Haskell2010
+
+-- Builds the executable 'clash', with rvFormal project in scope
+executable clash
+  main-is: bin/Clash.hs
+  default-language: Haskell2010
+  Build-Depends: base, clash-ghc, rvFormal
+  if !os(Windows)
+    ghc-options: -dynamic
+
+-- Builds the executable 'clashi', with rvFormal project in scope
+executable clashi
+  main-is: bin/Clashi.hs
+  default-language: Haskell2010
+  if !os(Windows)
+    ghc-options: -dynamic
+  build-depends: base, clash-ghc, rvFormal
+
+executable main
+  import: common-options
+  main-is: bin/Main.hs
+  -- hs-source-dirs: hs
+  default-language: Haskell2010
+  build-depends:
+    base,
+    clash-ghc,
+    rvFormal
+  c-sources: c/uart_sim_device.c
+  include-dirs: c
+  if !os(Windows)
+    ghc-options: -dynamic