*** The syntax-directed buffer-scan functions (such as
`parse-partial-sexp', `forward-word' and similar functions) can now
obey syntax information specified by text properties, if the variable
`parse-sexp-lookup-properties' is non-nil.
If the value of `parse-sexp-lookup-properties' is nil, the behavior is as before: the syntax-table of the current buffer is always used to determine the syntax of the character at the position.
When `parse-sexp-lookup-properties' is non-nil, the syntax of a character in the buffer is calculated thus:
a) if the `syntax-table' text-property of that character is a cons, this cons becomes the syntax-type;
Valid values of `syntax-table' text-property are: nil, a valid syntax-table, and a valid syntax-table element, i.e., a cons cell of the form (SYNTAX-CODE . MATCHING-CHAR).
b) if the character's `syntax-table' text-property is a syntax table, this syntax table is used (instead of the syntax-table of the current buffer) to determine the syntax type of the character.
c) otherwise the syntax-type is determined by the syntax-table of the current buffer.