RFR: 8300168: Typo in AccessibleJTableHeaderEntry javadoc

[Abhishek Kumar]

There was a typo error in method description of `public AccessibleJTableHeaderEntry(int c, JTableHeader p, JTable t)`. Replaced the text `AccessiblJTableHeaaderEntry` with `AccessibleJTableHeaderEntry`.

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

Commit messages:
 - Typo error fix

Changes: https://git.openjdk.org/jdk/pull/12024/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12024&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8300168
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12024.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12024/head:pull/12024

PR: https://git.openjdk.org/jdk/pull/12024