chore: updating docs to clang16 (#1875)

For #1542 I have changed all of the documentation mentions of clang15
and I didn't find a good place to include this in the `docs` as it
seemed like that documentation had to do with developing using aztec
packages instead of doing dev work on the aztec packages repo itself.

Outside of documentation would you like to see all of the
`bootstrap.sh`, `CMakePresents.json`, and `Dockerfile` changed to
clang16 as well @ludamad? Here are some examples of what I am referring
to:


https://github.com/jtfirek/aztec-packages/blob/e189a78db523abf334b39d4bebad48a317ae46c6/circuits/cpp/barretenberg/sol/bootstrap.sh#L21


https://github.com/jtfirek/aztec-packages/blob/e189a78db523abf334b39d4bebad48a317ae46c6/circuits/cpp/CMakePresets.json#L41


https://github.com/jtfirek/aztec-packages/blob/e189a78db523abf334b39d4bebad48a317ae46c6/circuits/cpp/barretenberg/cpp/dockerfiles/Dockerfile.circuits-x86_64-linux-clang-builder-runner#L7

circuits/README.md

@@ -14,7 +14,7 @@ The [`aztec3-circuits`](https://github.com/AztecProtocol/aztec3-packages) circui
 
 - cmake >= 3.24
 - Ninja (used by the presets as the default generator)
-- clang15
+- clang16
 - clang-format
 - wasm-opt (part of the [Binaryen](https://github.com/WebAssembly/binaryen) toolkit)
 - [wasmtime](https://docs.wasmtime.dev/cli-install.html) for running tests in a wasm environment
@@ -161,9 +161,9 @@ It may be useful to view coverage information from within vscode. The `./scripts
    - Open the command pallete (`Ctrl+Shift+P`)
    - Type and select "CMake: Select Configure Preset"
    - Choose a debug preset such as:
-     - "Debugging build with Clang-15"
+     - "Debugging build with Clang-16"
      - "Debugging build for WASM"
-   - Redo this step later to switch between Clang-15/native and wasm
+   - Redo this step later to switch between Clang-16/native and wasm
 1. Go to the "Run and Debug" panel
    - Button (usually on left) that looks like a play button with a bug
    - Or `Ctrl+Shift+D`
@@ -180,7 +180,7 @@ It may be useful to view coverage information from within vscode. The `./scripts
    - Don't commit these changes
 1. [OPTIONAL] set breakpoints in C++ files
 
-> _Note:_ redo steps 3-5 to switch between debugging Clang-15/native test executables and WASM test executables
+> _Note:_ redo steps 3-5 to switch between debugging Clang-16/native test executables and WASM test executables
 
 ---