Fixed a name inconsistency in generic mech shells

[TurklerRS]

Changes

Changed the name of the generic mechanoid shell (Incendiary) item to mech shell (Incendiary)

Yes, I know this is a very minor nitpick.

Reasoning

The ammo sets and the recipes of incendiary mech shells refer to the item as mech shells. The item for the other mech shell type - demolition - is also called a mech shell. This seems to be an oversight.

Alternatives

Rename all mech shells to mechanoid shells.

Testing

Check tests you have performed:

• [ ] Compiles without warnings
• [X] Game runs without errors (Tested with changes thrown into compiled dev version)
• [X] Playtested a colony (2 minutes, spawned the items in)

[github-actions[bot]]

You can download the rebuilt assembly for this PR here: https://combatextended.lp-programming.com/CombatExtended-10990935586.zip