Clarify Pauli Twirling and error mitigation vs suppression

docs/guides/configure-error-mitigation.ipynb

@@ -65,7 +65,7 @@
     "query. Error mitigation reduces errors (bias) in results by processing\n",
     "the outputs from a collection, or ensemble, of related circuits. The\n",
     "degree of error reduction depends on the method applied. The resilience\n",
-    "level abstracts the detailed choice of error mitigation method to allow\n",
+    "level abstracts the detailed choice of error mitigation (or error correction) method to allow\n",
     "users to reason about the cost/accuracy trade that is appropriate to\n",
     "their application.\n",
     "\n",
@@ -89,7 +89,7 @@
     "|------------------|-------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------|\n",
     "| 0                | No mitigation                                                                                         | None                                                                      |\n",
     "| 1 [Default]      | Minimal mitigation costs: Mitigate error associated with readout errors                               | Twirled Readout Error eXtinction  (TREX) measurement twirling             |\n",
-    "| 2                | Medium mitigation costs. Typically reduces bias in estimators, but is not guaranteed to be zero-bias. | Level 1 + Zero Noise Extrapolation (ZNE) and gate twirling\n",
+    "| 2                | Medium mitigation costs. Typically reduces bias in estimators, but is not guaranteed to be zero-bias. | Level 1 + Zero Noise Extrapolation (ZNE), as well as gate twirling (error suppression)\n",
     "\n",
     "\n",
     "<Admonition type=\"info\" title=\"Attention\">\n",

docs/guides/error-mitigation-and-suppression-techniques.ipynb

@@ -120,7 +120,7 @@
     "\n",
     "Twirling, also known as [randomized compiling](https://journals.aps.org/pra/abstract/10.1103/PhysRevA.94.052325), is a widely used technique for converting arbitrary noise channels into noise channels with more specific structure.\n",
     "\n",
-    "Pauli twirling is a special kind of twirling that uses Pauli operations. It has the effect of transforming any quantum channel into a Pauli channel. Performed alone, it can mitigate coherent noise because coherent noise tends to accumulate quadratically with the number of operations, whereas Pauli noise accumulates linearly. Pauli twirling is often combined with other error mitigation techniques that work better with Pauli noise than with arbitrary noise.\n",
+    "Pauli twirling is a special kind of twirling that uses Pauli operations. It has the effect of transforming any quantum channel into a Pauli channel. Performed alone, it can mitigate coherent noise because coherent noise tends to accumulate quadratically with the number of operations, whereas Pauli noise accumulates linearly. Pauli twirling is often combined with error mitigation techniques that work better with Pauli noise than with arbitrary noise.\n",
     "\n",
     "Pauli twirling is implemented by sandwiching a chosen set of gates with randomly chosen single-qubit Pauli gates in such a way that the ideal effect of the gate remains the same. The result is that a single circuit is replaced with a random ensemble of circuits, all with the same ideal effect. When sampling the circuit, samples are drawn from multiple random instances, rather than just a single one.\n",
     "\n",