capitalization fixes

Library/Homebrew/brew.sh

Library/Homebrew/build.rb

Library/Homebrew/cask/cmd/internal_stanza.rb

Library/Homebrew/cask/dsl/caveats.rb

Library/Homebrew/cask/installer.rb

Library/Homebrew/cmd/update.sh

Library/Homebrew/dev-cmd/bump-formula-pr.rb

Library/Homebrew/dev-cmd/create.rb

Library/Homebrew/dev-cmd/edit.rb

Library/Homebrew/dev-cmd/unpack.rb

Library/Homebrew/diagnostic.rb

Library/Homebrew/extend/pathname.rb

Library/Homebrew/formula.rb

Library/Homebrew/language/go.rb

Library/Homebrew/livecheck/livecheck.rb

Library/Homebrew/rubocops/urls.rb

Library/Homebrew/sandbox.rb

Library/Homebrew/tap.rb

Library/Homebrew/test.rb

Library/Homebrew/test/bash_spec.rb