Javadoc code completion for inline tags misses a space

* Have the cursor inside Javadoc
* type "@"
* trigger code completion
* select "{@code}", return

Result "{@code|}" (where | denotes the cursor). The user always has to type a blank before writing the actual tag content. To me it looks like this was caused by https://bugs.eclipse.org/bugs/show_bug.cgi?id=121026. That issue was about having one blank too much when _wrapping_ existing characters into inline tags via code completion. Unfortunately the fix modified both the code for just inserting the plain tag and the code for wrapping. Half of the patch needs to be reverted therefore.

I'll provide a fix.