Corrected: leoAst.py creates two-way links between tokens and ast nodes

In the initial announcement, the link to leoAst.py was incorrect. The correct link is to leoAst.py in Leo's "devel" branch: https://github.com/leo-editor/leo-editor/blob/devel/leo/core/leoAst.py Alas, the link did not generate a 404, but instead linked to way obsolete code. My apologies for the

ANN: leoAst.py creates two-way links between tokens and ast nodes

*Overview* leoAst.py unifies python's token-oriented and ast-oriented worlds. leoAst.py defines classes that create two-way links between *tokens* created by python's tokenize module