bump-cask-pr: replace "host" naming with "current"

`Homebrew::SimulateSystem.current_os` may be returning the host OS or
a simulated OS and we can't be sure which in this context. At the
moment, this is expected to be the host OS but that may change in the
future. It shouldn't matter on a technical level but using "host" in
these variable names may lead to confusion.

This replaces "host" in names with "current", as it more accurately
describes the information.

Author: samford

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

@@ -183,8 +183,8 @@ def shortened_version(version, cask:)
 
       sig { params(cask: Cask::Cask).returns(T::Array[[Symbol, Symbol]]) }
       def generate_system_options(cask)
-        host_os = Homebrew::SimulateSystem.current_os
-        host_is_macos = MacOSVersion::SYMBOLS.include?(host_os)
+        current_os = Homebrew::SimulateSystem.current_os
+        current_os_is_macos = MacOSVersion::SYMBOLS.include?(current_os)
         newest_macos = MacOSVersion::SYMBOLS.keys.first
 
         depends_on_archs = cask.depends_on.arch&.filter_map { |arch| arch[:type] }&.uniq
@@ -197,7 +197,7 @@ def generate_system_options(cask)
         if cask.on_system_blocks_exist?
           OnSystem::BASE_OS_OPTIONS.each do |os|
             os_values << if os == :macos
-              (host_is_macos ? host_os : newest_macos)
+              (current_os_is_macos ? current_os : newest_macos)
             else
               os
             end
@@ -208,7 +208,7 @@ def generate_system_options(cask)
           # Architecture is only relevant if on_system blocks are present or
           # the cask uses `depends_on arch`, otherwise we default to ARM for
           # consistency.
-          os_values << (host_is_macos ? host_os : newest_macos)
+          os_values << (current_os_is_macos ? current_os : newest_macos)
           arch_values << :arm if arch_values.empty?
         end