RFR: 8231186: Replace html tag <code>foo</code> with javadoc tag {@code foo} in java.base

[Martin Buchholz]

I recall thinking that many of the <code> should actually be changed
to @link since use of <code> suggested ancient times before @link became
available.
But "Perfect is the enemy of good".

 /**
- * A <code>BufferedInputStream</code> adds
+ * A {@code BufferedInputStream} adds
  * functionality to another input stream-namely,
  * the ability to buffer the input and to
- * support the <code>mark</code> and <code>reset</code>
- * methods. When  the <code>BufferedInputStream</code>
+ * support the {@code mark} and {@code reset}
+ * methods. When  the {@code BufferedInputStream}
  * is created, an internal buffer array is
  * created. As bytes  from the stream are read
  * or skipped, the internal buffer is refilled
  * as necessary  from the contained input stream,
- * many bytes at a time. The <code>mark</code>
+ * many bytes at a time. The {@code mark}
  * operation  remembers a point in the input
- * stream and the <code>reset</code> operation
+ * stream and the {@code reset} operation