docs: Update installation info for bb and noir (#8119)

People trip up on not having jq installed when noir instructions tell
them to use the bb command.
Update both to smooth this out.

---------

Co-authored-by: Tom French <15848336+TomAFrench@users.noreply.github.com>

barretenberg/cpp/src/barretenberg/bb/readme.md

@@ -3,8 +3,7 @@
 ### Why is this needed?
 
 Barretenberg is a library that allows one to create and verify proofs. One way to specify the circuit that one will use to create and verify
-proofs over is to use the Barretenberg standard library. Another way, which pertains to this module is to supply the circuit description using 
-an IR called [ACIR](https://github.com/noir-lang/acvm).
+proofs over is to use the Barretenberg standard library. Another way, which pertains to this module is to supply the circuit description using an IR called [ACIR](https://github.com/noir-lang/acvm).
 
 This binary will take as input ACIR and witness values described in the IR to create proofs.
 
@@ -35,7 +34,7 @@ This binary will take as input ACIR and witness values described in the IR to cr
     ```
 
     Check the version compatibility section below for how to identify matching versions.
-    
+
 4. Check if the installation was successful:
 
     ```bash
@@ -44,6 +43,10 @@ This binary will take as input ACIR and witness values described in the IR to cr
 
 If installation was successful, the command would print the version of `bb` installed.
 
+### Usage prerequisites
+
+Certain `bb` commands will expect the tool `jq` to already be installed. If `jq -V` doesn't return a version number, install it from [here](https://jqlang.github.io/jq/download/).
+
 ### Version compatibility with Noir
 
 TODO: https://github.com/AztecProtocol/aztec-packages/issues/7511