riscv-elf: Spelling fix

Author: jrtc27

riscv-elf.adoc

@@ -136,7 +136,7 @@ into literal pools, a 64-bit address literal can be loaded from the pool.
 NOTE: Because calculating the pool entry address must use `auipc` and
 `addi` or `ld`, each pool entry has to be located within the range
 between -2GiB and +2GiB from its access intructions.  In general, the pool
-is appeneded in .text section or put into .rodata section.
+is appended in .text section or put into .rodata section.
 
 [,asm]
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