Function createSimpleLexer

Given triples of [style, pattern, context] returns a lexing function, * The lexing function interprets the patterns to find token boundaries and * returns a decoration list of the form * [index_0, style_0, index_1, style_1, ..., index_n, style_n] * where index_n is an index into the

(shortcutStylePatterns, fallthroughStylePatterns)