Toolshed (#17895)

* ogh

* i should save my work

* ogh

* hhcdfhjbghshbxdfhghshc
- lots of bugs in parsing still
- invocation is a stub

* expr parsing works

* awawa

* Saving work

* Improve APIs a bit all around, add shortcuts.

* awa

* awa

* AAAAAA

* save work

* Move shit to engine

* lord

* bql is kill

* forgot the fucking bike rack

* bql is kill for real

* pjb will kill me

* aughfhbdj

* adgddf

* gdsgvfvxshngfgh

* b

* hfsjhghj

* a

* tf you mean i have to document it

* follow C# standards

* Assorted cleanup and documentation pass, minor bugfix in ValueRefParser.

* Start porting old commands, remove that pesky prefix in favor of integrating with the shell.

* bw

* Fix valueref up a bit, improve autocomplete for it.

* awa

* fix tests

* git shut up

* Arithmetic commands.

* parse improvements

* Update engine.

---------

Co-authored-by: moonheart08 <moonheart08@users.noreply.github.com>

Content.IntegrationTests/Tests/Toolshed/LocTest.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using System.Linq;
+using Robust.Shared.Toolshed;
+
+namespace Content.IntegrationTests.Tests.Toolshed;
+
+[TestFixture]
+public sealed class LocTest : ToolshedTest
+{
+    [Test]
+    public async Task AllCommandsHaveDescriptions()
+    {
+        await Server.WaitAssertion(() =>
+        {
+            Assert.That(InvokeCommand("cmd:list where { cmd:descloc loc:tryloc isnull }", out var res));
+            Assert.That((IEnumerable<CommandSpec>)res, Is.Empty, "All commands must have localized descriptions.");
+        });
+    }
+}