More food price fixes.
Merge pull request #7578 from Rivet-the-Zombie/moar-fixes

More food price fixes.
Remove unused function default_technique_name
Remove unused variable tech_id_lookup

And remove the function initializes it.
Remove the unused enumeration technique_id.
Remove another unused variable: Item_factor::techniques_list
Remove another unused function: item::sort_rank

It is obsolete since the introduction of item categories as a separate class.
ma_technique: add name member to be shown for techniques of items.

Item_factory: when checking item definitions, check the technique, too.

Add simple definitions of the legacy techniques that some items have (WBLOCK, DEF_DISARM, GRAB)

Changed zweifire_off: moved "SHEATH_SWORD" from techniques to flags, because it's a flag.