Rename BuildHelper#copy_to_gem_home to copy_to_gem

- Rename the method copy_to_gem_home to copy_to_gem to simplify the name and better reflect its functionality.

lib/ocran/build_helper.rb

@@ -9,7 +9,7 @@ def copy_to_bin(source, target)
       cp(source, BINDIR / target)
     end
 
-    def copy_to_gem_home(source, target)
+    def copy_to_gem(source, target)
       cp(source, GEMDIR / target)
     end
 
@@ -22,7 +22,7 @@ def duplicate_to_exec_prefix(source)
     end
 
     def duplicate_to_gem_home(source, gem_path)
-      copy_to_gem_home(source, Pathname(source).relative_path_from(gem_path))
+      copy_to_gem(source, Pathname(source).relative_path_from(gem_path))
     end
 
     # Sets an environment variable with a joined path value.