Replace `glsentryname` by `glsentrytext`

[loicreynier]

In some advanced cases, the name and text fields may be distinct. However, adding a syntax to distinguish them seems overkill to me. name is the text printed in the glossary list nad text is the text printed in the document body. Knowing that text defaults to name if not defined, having a syntax for \glsentrytext seems to be the best approach to me.