Keep glossary definition of codegen

Author: Alex Kitchens

src/appendix/glossary.md

@@ -9,6 +9,7 @@ Term                    | Meaning
 AST                     |  the abstract syntax tree produced by the syntax crate; reflects user syntax very closely.
 binder                  |  a "binder" is a place where a variable or type is declared; for example, the `<T>` is a binder for the generic type parameter `T` in `fn foo<T>(..)`, and \|`a`\|` ...` is a binder for the parameter `a`. See [the background chapter for more](./appendix/background.html#free-vs-bound)
 bound variable          |  a "bound variable" is one that is declared within an expression/term. For example, the variable `a` is bound within the closure expession \|`a`\|` a * 2`. See [the background chapter for more](./appendix/background.html#free-vs-bound)
+codegen                 |  the code to translate MIR into LLVM IR.
 codegen unit            |  when we produce LLVM IR, we group the Rust code into a number of codegen units. Each of these units is processed by LLVM independently from one another, enabling parallelism. They are also the unit of incremental re-use.
 completeness            |  completeness is a technical term in type theory. Completeness means that every type-safe program also type-checks. Having both soundness and completeness is very hard, and usually soundness is more important. (see "soundness").
 control-flow graph      |  a representation of the control-flow of a program; see [the background chapter for more](./appendix/background.html#cfg)
@@ -61,7 +62,7 @@ tcx                     |  the "typing context", main data structure of the comp
 trait reference         |  the name of a trait along with a suitable set of input type/lifetimes ([see more](./traits/goals-and-clauses.html#trait-ref))
 token                   |  the smallest unit of parsing. Tokens are produced after lexing ([see more](the-parser.html)).
 [TLS]                   |  Thread-Local Storage. Variables may be defined so that each thread has its own copy (rather than all threads sharing the variable). This has some interactions with LLVM. Not all platforms support TLS.
-codegen                 |  the code to translate MIR into LLVM IR.
+trans                   |  the code to translate MIR into LLVM IR. Renamed to codegen.
 trait reference         |  a trait and values for its type parameters ([see more](ty.html)).
 ty                      |  the internal representation of a type ([see more](ty.html)).
 UFCS                    |  Universal Function Call Syntax. An unambiguous syntax for calling a method ([see more](type-checking.html)).