RFR: 8284908: Refine diagnostic positions for DCErroneous

[Pavel Rappo]

Before:

Standard Doclet version 18+36-2087
Building tree for all the packages and classes...
Generating /tmp/whatever/ExampleDiagnostics.html...
ExampleDiagnostics.java:5: error: unexpected content
     * {@docRoot a}
       ^
ExampleDiagnostics.java:11: error: unexpected content
     * {@inheritDoc a}
       ^
ExampleDiagnostics.java:17: error: '>' expected
     * @param <T param
                     ^

After:

Standard Doclet version 19-internal-2022-04-07-1105474.pavelrappo...
Building tree for all the packages and classes...
Generating /tmp/whatever/ExampleDiagnostics.html...
ExampleDiagnostics.java:5: error: unexpected content
     * {@docRoot a}
                 ^
ExampleDiagnostics.java:11: error: unexpected content
     * {@inheritDoc a}
                    ^
ExampleDiagnostics.java:17: error: '>' expected
     * @param <T param
                ^

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

Commit messages:
 - Update copyright years
 - Specify preferred diagnostic positions
 - Print prefPos in header if prefPos is defined

Changes: https://git.openjdk.java.net/jdk/pull/8264/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8264&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284908
  Stats: 67 lines in 14 files changed: 19 ins; 0 del; 48 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8264.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8264/head:pull/8264

PR: https://git.openjdk.java.net/jdk/pull/8264