weapons: add tests to confirm melee weapon value and adjust some weapons (part 3)

[mlangsdorf]

Summary

SUMMARY: Balance "weapons: add tests to confirm melee weapon value and adjust some weapons (part 3)"

Purpose of change

As part of the great melee weapon rebalance (#39644 et al), @Brian-Otten unfortunately forgot to adjust a couple of weapons' accuracy values. Also, although effective DPS tests were added around this time, no tests were added to make sure that melee weapon's have appropriate value and to
detect future changes that would change the value of melee weapons.

Rectify these issues by adding an additional set of tests that calculate the weapon value of various weapons against a fairly beefy reference avatar (all stats 10, all skills 4). Then rebalance some weapons.

This is part 3, which follows #41089 and covers two handed swords, swords, and knives.

Describe the solution

The tests just check if a given weapon has a given weapon_value, +/- 0.75.

Some weapons had their to-hit, mass, volume, and/or damages updated to bring them in line with expected values for similar weapons. Most noticeably, many knives got their accuracy reduced since they are extremely short weapons with point strike surfaces, and in the case of kitchen and utility knives, aren't balanced for combat.

Describe alternatives you've considered

"to_hit" as a static number needs to be replaced by an object:

"accuracy": {
  "length": "short",  // could be long, short, or none
  "grip": "weapon", // could be none, poor, solid, or weapon
  "surface": "point", // could be point, line, every, or any
  "balance": "good" // could clumsy, uneven, neutral, or good
}

with the meaning of the terms taken from doc/GAME_BALANCE.md and itemfactory.cpp parsing the descriptive terms and generating an actual to_hit value. The object would make it a lot clearer as to what was going on. It would also be a lot more work, so I didn't do it in this PR series but will probably start on it soon. I'll keep the legacy "to_hit" values around for compatibility for out of tree mods.

[Zireael07]

Linguistic nit: plural of knife is knives not knifes :P

[mlangsdorf]

Bah, stupid rules of Old English grammar. Nitpick picked.