Began implementing fully isomorphic macros

Like Rust's Proc macros. Now we have preprocessor recursion to worry about. I also made a cool macro for enums

orchid-api/src/location.rs

@@ -2,13 +2,17 @@ use std::ops::Range;
 
 use orchid_api_derive::Coding;
 
-use crate::interner::TStrv;
+use crate::{TStr, TStrv};
 
 #[derive(Clone, Debug, Coding)]
 pub enum Location {
+  /// Location inaccessible. Locations are always debugging aids and never
+  /// mandatory.
   None,
+  /// Associated with a slot when wrapped in an expression.
+  SlotTarget,
   /// Used in functions to denote the generated code that carries on the
-  /// location of the call. Not allowed in the const tree.
+  /// location of the call.
   Inherit,
   Gen(CodeGenInfo),
   /// Range and file
@@ -26,5 +30,5 @@ pub struct SourceRange {
 #[derive(Clone, Debug, Coding)]
 pub struct CodeGenInfo {
   pub generator: TStrv,
-  pub details: String,
+  pub details: TStr,
 }