Add "memoise" to the glossary

Author: varkor

src/appendix/glossary.md

@@ -42,6 +42,7 @@ late-bound lifetime     |  a lifetime region, which is bound in a HRTB and subst
 local crate             |  the crate currently being compiled.
 LTO                     |  Link-Time Optimizations. A set of optimizations offered by LLVM that occur just before the final binary is linked. These include optimizations like removing functions that are never used in the final program, for example. _ThinLTO_ is a variant of LTO that aims to be a bit more scalable and efficient, but possibly sacrifices some optimizations. You may also read issues in the Rust repo about "FatLTO", which is the loving nickname given to non-Thin LTO. LLVM documentation: [here][lto] and [here][thinlto]
 [LLVM]                  |  (actually not an acronym :P) an open-source compiler backend. It accepts LLVM IR and outputs native binaries. Various languages (e.g. Rust) can then implement a compiler front-end that output LLVM IR and use LLVM to compile to all the platforms LLVM supports.
+memoise                 |  memoisation is the process of storing the results of (pure) computations (such as pure function calls) to avoid having to repeat them in the future. This is generally a trade-off between execution speed and memory usage.
 MIR                     |  the Mid-level IR that is created after type-checking for use by borrowck and codegen ([see more](../mir/index.html))
 miri                    |  an interpreter for MIR used for constant evaluation ([see more](../miri.html))
 normalize               |  a general term for converting to a more canonical form, but in the case of rustc typically refers to [associated type normalization](../traits/associated-types.html#normalize)