gdb/ChangeLog: Update copyright year range in all GDB files
This applies the second part of GDB's End of Year Procedure, which updates the copyright year range in all of GDB's files. gdb/ChangeLog: Update copyright year range in all GDB files.
gdb/ChangeLog: Update year range in copyright notice of all files.
gdb/ChangeLog: PR 15276 * NEWS: Mention $_caller_is, $_caller_matches, $_any_caller_is, $_any_caller_matches. * data-directory/Makefile.in (PYTHON_FILE_LIST): Add caller_is.py. * python/lib/gdb/function/caller_is.py: New file. gdb/testsuite/ChangeLog: PR 15276 * gdb.python/py-caller-is.c: New file. * gdb.python/py-caller-is.exp: New file. gdb/doc/ChangeLog: PR 15276 * gdb.texinfo (Convenience Funs): Document $_caller_is, $_caller_matches, $_any_caller_is, $_any_caller_matches.