I think it’s an interesting idea. However, I find the <a id="link-text"></a> without content, without href and outside any paragraph, a bit strange. A bit better to use <span id="link-text"></span>.
But personally, I find the proposed span-syntax more natural anyway (which could default to generating an id if no attributes are provided):
The [link text]{} cannot contain links, though it may
contain images. Etc.
... later ...
See the discussion of [link text], above.
Or even an attribute on the entire paragraph:
The link text cannot contain links, though it may
contain images. Etc.
{#link-text}
... later ...
See the discussion of [link text], above.