coverage.c: Refer to "notes file" instead of "graph file" in all comments.
gcc/
* coverage.c: Refer to "notes file" instead of "graph file"
in all comments. Explain history of bbg prefix.
* gcov-io.h: Likewise.
* gcov.c: Likewise.
(find_source): Likewise in fnotice.
(read_graph_file): Likewise.
(read_count_file): Likewise.
* doc/gcov.texi: Document -fprofile-dir flag. Add "notes file"
and "data file" explicitly in the explanation of the files.