Adds goquery.Text(s, *TextOptions), a package-level counterpart to the
Selection.Text method that gives control over how the text of distinct
text nodes is joined (Separator), whether each node is trimmed of
surrounding whitespace (Trim), and which text nodes are included (Keep).
This covers the common need to extract clean, readable text from a
document - for example joining fragments with a space and dropping the
text of script/style elements - without hand-rolling a node walk.
Passing a nil TextOptions keeps the behaviour identical to Selection.Text.
Includes tests and a runnable example.
Chris (ChrisJr404)