Fix broken links in @ChangeId javadoc.

We will soon have javadoc generated from the doc comments on all
@ChangeId annotated constants. Since the link target referred to
here is a @hide constant, it cannot be resolved as part of DAC doc
generation. Replace it with {@code} specifying the constants value
instead.

Bug: 144927670
Test: In follow up CLs
Change-Id: I9947e722dca228705190e8f2c49e47104c04dea6