Update offset field name in encode API doc (#5993)

Updates the documentation for various encode APIs to correctly state that
the offset field of instr_t is used for instr_t target offset computation, instead
of the note field which was used prior to #5791.

core/ir/encode_api.h

@@ -132,7 +132,7 @@ DR_API
  * Encodes \p instr into the memory at \p pc.
  * Uses the x86/x64 mode stored in instr, not the mode of the current thread.
  * Returns the pc after the encoded instr, or NULL if the encoding failed.
- * If instr is a cti with an instr_t target, the note fields of instr and
+ * If instr is a cti with an instr_t target, the offset fields of instr and
  * of the target must be set with the respective offsets of each instr_t!
  * (instrlist_encode does this automatically, if the target is in the list).
  * x86 instructions can occupy up to 17 bytes, so the caller should ensure
@@ -154,7 +154,7 @@ DR_API
  *
  * Uses the x86/x64 mode stored in instr, not the mode of the current thread.
  * Returns the pc after the encoded instr, or NULL if the encoding failed.
- * If instr is a cti with an instr_t target, the note fields of instr and
+ * If instr is a cti with an instr_t target, the offset fields of instr and
  * of the target must be set with the respective offsets of each instr_t!
  * (instrlist_encode does this automatically, if the target is in the list).
  * x86 instructions can occupy up to 17 bytes, so the caller should ensure
@@ -175,8 +175,8 @@ DR_API
  * Uses the x86/x64 mode stored in each instr, not the mode of the current thread.
  * In order for instr_t operands to be encoded properly,
  * \p has_instr_jmp_targets must be true.  If \p has_instr_jmp_targets is true,
- * the note field of each instr_t in ilist will be overwritten, and if any
- * instr_t targets are not in \p ilist, they must have their note fields set with
+ * the offset field of each instr_t in ilist will be overwritten, and if any
+ * instr_t targets are not in \p ilist, they must have their offset fields set with
  * their offsets relative to pc.
  * x86 instructions can occupy up to 17 bytes each, so the caller should ensure
  * the target location has enough room to avoid overflow.
@@ -200,8 +200,8 @@ DR_API
  *
  * In order for instr_t operands to be encoded properly,
  * \p has_instr_jmp_targets must be true.  If \p has_instr_jmp_targets is true,
- * the note field of each instr_t in ilist will be overwritten, and if any
- * instr_t targets are not in \p ilist, they must have their note fields set with
+ * the offset field of each instr_t in ilist will be overwritten, and if any
+ * instr_t targets are not in \p ilist, they must have their offset fields set with
  * their offsets relative to pc.
  *
  * If \p max_pc is non-NULL, computes the total size required to encode the