add categories to item types
IV mutagen insertion

These add IV mutagens to the Lab chem rooms; each is comparatively rare
but the amount of them should make the odds of one or two reasonable.  I
intentionally made Fish more common because there's no renewable way to
make it, IIRC: you need canned goods.

Also makes flavored mutagens recipe-locked (so, major Nerf) and includes
recipe books for all of them, which tend to spawn in relevant lab rooms.
But if you find one on a scicorpse, that's not a bug.  Check the item
ID.  :-)

Finally, adds lab notes to the computers to keep the backstory-support
going.
quotes v. semicolon

Fixed typo.
Added border and header to input context help
fix-string-overlapping-in-ranged-help
header renamed + comment fix
ident fix
fix memleak in input_context::display_help()
add ESC key to exit from search result
try-to-fix-help-displaying
null checking gone wild
remove comment
prevent accessing invalid monster instances
Correct the policecar's id usage.
use a dedicated item_category class
add bio_lockpick as item
fix leading 0 in tile_config.json
fix wrong comparison
Tweaked the Makeshift Knife

Allowed the recipe to use 100 sinew, thread, or plant fiber as well as
two units of six inch string alongside existing materials.
Merge pull request #4897 from EkarusRyndren/TweaksTheKnife

Tweaked the Makeshift Knife