GeezerVison

Conflicts with #43 and #44 in ImportOrderer, RemoveUnusedImports and
their tests.

ImportOrderer: an import now carries both the comments on the lines
before it, from #44, and its declaration rendered from its toks, from
this branch (palantir#1707). This branch's loop
over same-line block comments already covers #44's single block comment
after the `;`, so #44's copy of that step goes. Two interactions are
decided here:

- A javadoc comment right after an import's `;` is no longer an error.
  This branch rejected it because the formatter moves it onto a line of
  its own, which used to separate the imports. Since #44 a comment
  between imports goes with the import after it, and so does this one.
- Two copies of an import that differ only in the comment on the lines
  before them no longer collapse into one, so that comment stays. This
  branch already kept copies that differ in a comment inside the
  declaration.

RemoveUnusedImports: this branch's loop over JCTree with
Trees.getEndPosition, and #43's coalesced ranges and blank-line cleanup.

Tests: every case from both sides. This branch's case for a same-line
block comment repeated #44's and is folded into it. Its javadoc case now
expects the comment to move with the next import. A new case covers the
duplicate.

Checked: all 1493 formatter tests pass. On the JDK 21 sources (15,747
files, Temurin 21) and the JDK 25 sources (15,368 files, Corretto 25),
the merge formats every file exactly as main does, with no errors.