Updated some of the text entries in 'technical and financial parameters'...

... popup table for etmodel issue [#1684](https://github.com/quintel/etmodel/issues/1684). Note that 'app/models/api/v3/converter_presenter_data.rb' actually does state the heat efficiency units should be '%' despite the screenshot in [#1684](https://github.com/quintel/etmodel/issues/1684) suggesting this does not show up.