Fix typos in challenges

docs/contents/challenges.md

@@ -10,4 +10,4 @@ Besides the register, other elements like the SLM used to target individual qubi
 
 Primitive operations are another challenge in neutral atoms. The analog nature of the algorithms and device makes it difficult to clearly define “primitive operations”. Elementary structures like a pulse corresponding to the neutral atom Hamiltonian and an idle/wait instruction to let the qubits interact under free coupling (without drive).
 
-To avoid define a fixed set of operations that may not reflect the hardware capabilities and to avoid constant changes in the IR definition to include new primitives, the instructions’ names are passed as labels like `QuInstrunct("dyn_pulse",…)` and `QuInstruct("rx".…)` instead of `Pulse(…)` and `RX(…)`. This may change in the future. However, right now, this flexibility allows us to explore the hardware's capabilities without being held by a particular set of instructions.
+To avoid define a fixed set of operations that may not reflect the hardware capabilities and to avoid constant changes in the IR definition to include new primitives, the instructions’ names are passed as labels like `QuInstrunct("dyn_pulse", …)` and `QuInstruct("rx", …)` instead of `Pulse(…)` and `RX(…)`. This may change in the future. However, right now, this flexibility allows us to explore the hardware's capabilities without being held by a particular set of instructions.