RFR: 8330178: Clean up non-standard use of /** comments in `java.base` [v2]

[Jonathan Gibbons]

> Please review a set of updates to clean up use of `/**` comments in the vicinity of declarations.
> 
> There are various categories of update:
> 
> * "Box comments" beginning with `/**`
> * Misplaced doc comments before package or import statements
> * Misplaced doc comments after the annotations for a declaration
> * Dangling `/**` comments relating to a group of declarations, separate from the doc comments for each of those declarations
> * Use of `/**` for the legal header at or near the top of the file
> 
> In one case, two doc comments before a declaration were merged, which fixes a bug/omission in the documented serialized form.

Jonathan Gibbons has updated the pull request incrementally with one additional commit since the last revision:

  Update src/java.base/share/classes/sun/net/www/protocol/file/FileURLConnection.java
  
  Fix grammatical typo
  
  Co-authored-by: Alexey Ivanov <alexey.ivanov at oracle.com>

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18846/files
  - new: https://git.openjdk.org/jdk/pull/18846/files/fcbe02d5..d7b46a85

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18846&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18846&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18846.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18846/head:pull/18846

PR: https://git.openjdk.org/jdk/pull/18846