Fix minor typo in dsa.c.

Author: Takeshi Ideriha
Discussion: https://postgr.es/m/4E72940DA2BF16479384A86D54D0988A6F3BF22D%40G01JPEXMBKW04

src/backend/utils/mmgr/dsa.c

@@ -650,7 +650,7 @@ dsa_pin_mapping(dsa_area *area)
  * will result in an ERROR.
  *
  * DSA_ALLOC_NO_OOM causes this function to return InvalidDsaPointer when
- * no memory is available or a size limit established by set_dsa_size_limit
+ * no memory is available or a size limit established by dsa_set_size_limit
  * would be exceeded.  Otherwise, such allocations will result in an ERROR.
  *
  * DSA_ALLOC_ZERO causes the allocated memory to be zeroed.  Otherwise, the