Closes #148.

TODO: Should more AJDE stuff be removed?
Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

This was required by the Eclipse team as one precondition for the next
release.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

An image which should be in its own paragraph was shown inline with the
text, somewhere to the right in the middle of a text paragraph. I
noticed while visually checking if docs generation still works as
expected after the last few commits, so I quickly fixed it.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

Many dozens (hundreds?) of documentation code blocks were indented to
match the surrounding XML or just arbitrarily. The thing is: Inside
<programlisting> tags, similar to <pre> tags, line feeds and leading
whitespace are being preserved, which looked very awkward in the HTML
documentation. While a few files were mostly correct in this respect,
which shows that it was meant to be like that, many others were not.
This was tedious, stupid work to fix, but it had to be done.

Please note that the documentation was in no way updated content-wise.
This is also overdue, but not my focus here.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

In two places, the documentation now contains this text:

"Since AspectJ 1.9.7, the obsolete Oracle/BEA JRockit agent is no longer
part of AspectJ. JRockit JDK never supported Java versions higher than
1.6. Several JRockit JVM features are now part of HotSpot and tools like
Mission Control available for OpenJDK and Oracle JDK."

The decision to drop JRockit support was made during a discussion
between Alexander Kriegisch and Andy Clement:

Andy Clement wrote on 26 Mar 2021:

> Yes I think so.
>
>
> Alexander Kriegisch wrote on 26 Mar 2021:
>
>> https://en.wikipedia.org/wiki/JRockit
>>
>> Can we get rid of that? AspectJ requires Java 8, JRockit never
>> supported more than Java 6.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

pbly some issue on abstract @Pointcut() in ajdt core - fix coming