Fix texinfo-3.12 problems:

Fix texinfo-3.12 problems:
* annotate.texi (Annotations): When GDBN omit @chapter and @node entry.
* gdb.texinfo: Check for @ifinfo instead of @ifnottex.
(rluser.texinfo, inc-hist.texinfo, annotate.texi): Add local @chapter
and @node entries.
* gdb.texinfo: Link all top-level nodes.
* inc-hist.texinfo: When GDBN omit the chapter/node.
* rluser.texinfo (Command Line Editing): Ditto.