neovim/cmake.packaging/WixPatch.xml

<CPackWiXPatch>
  <!--  Fragment ID is from: <your build dir>/_CPack_Packages/win64/WIX/files.wxs -->
  <CPackWiXFragment Id="CM_CP_bin.nvim.exe">
    <Environment
      Id='UpdatePath'
      Name='PATH'
      Action='set'
      Permanent='no'
      System='yes'
      Part='last'
      Value='[INSTALL_ROOT]bin'
    />
  </CPackWiXFragment>
</CPackWiXPatch>