cherry-pick from pi-dev docs: Fixing malformed javadoc

Several @link & @see javadoc directives were malformed, resulting in the
Javadoc code being output to the HTML.

Staged to:

http://go/dac-stage/reference/android/app/slice/Slice.Builder
http://go/dac-stage/reference/android/app/slice/SliceProvider
http://go/dac-stage/reference/android/text/style/ImageSpan
http://go/dac-stage/reference/android/content/ContentProvider

Bug: 120743732
Test: make ds-docs
Change-Id: I589644f8d266a116441409fbdaf7a0c533e0e356
Exempt-From-Owner-Approval: Doc-only change