datatype: misspell support with symbol table parser for error reporting

datatype: misspell support with symbol table parser for error reporting

Some datatypes provide a symbol table that is parsed as an integer.
Improve error reporting by using the misspell infrastructure, to provide
a hint to the user, whenever possible.

If base datatype, usually the integer datatype, fails to parse the
symbol, then try a fuzzy match on the symbol table to provide a hint
in case the user has mistype it.

For instance:

 test.nft:3:11-14: Error: Could not parse Differentiated Services Code Point expression; did you you mean `cs0`?
                 ip dscp ccs0
                         ^^^^

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>