std: fix HashMap RNG docs wording

library/std/src/collections/hash/map.rs

@@ -20,7 +20,7 @@
 /// reasonable best-effort is made to generate this seed from a high quality,
 /// secure source of randomness provided by the host without blocking the
 /// program. Because of this, the randomness of the seed depends on the output
-/// quality of the system's random number coroutine when the seed is created.
+/// quality of the system's random number generator when the seed is created.
 /// In particular, seeds generated when the system's entropy pool is abnormally
 /// low such as during system boot may be of a lower quality.
 ///