documentation issues in liblib and examples

[edhartnett]

Several doxygen documentation issues were found and fixed in liblib/nc_initialize.c and the C example programs under examples/C/.

liblib/nc_initialize.c

• Missing @file doxygen block — doxygen couldn't associate the file with its contents.
• nc_initialize() and nc_finalize() doc comments were internal-facing maintenance notes ("if you modify the format of NC_Dispatch, then you need to fix it everywhere") rather than user-facing API documentation. Replaced with descriptions of what the functions do, @return, and @see cross-references.
• Added a comment explaining the relationship between NETCDF_ENABLE_DAP, NETCDF_ENABLE_DAP2, and NETCDF_ENABLE_DAP4 macros, since the extern declarations and call sites use different guards.

examples/C — old-style doxygen headers

Six files used the old /*! \file doxygen syntax with bare copyright blocks and no @author tags. These were modernized to the /** @file style with descriptions and @author tags:

• simple_xy_wr.c
• simple.c
• file.c
• large_files.c
• met4D.c
• filter_example.c

examples/C — broken \ref copyright references

Four files referenced \ref copyright, which produces a doxygen warning unless a matching anchor exists. Replaced with plain text "See COPYRIGHT file for conditions of use":

• simple.c
• file.c
• large_files.c
• met4D.c

examples/C — missing @file block

• parallel_vara.c had no doxygen block at all. Added @file with description and @author.

examples/C — wrong description

• simple_xy_rd.c described itself as "Write a file demonstrating some of the features of netCDF-4" but it actually reads a simple classic netCDF file. Fixed to "Read a simple 2D netCDF file."

examples/C — duplicate #define UNITS

• pres_temp_4D_wr.c and pres_temp_4D_rd.c both had #define UNITS "units" defined twice (lines 38 and 49 in the writer, lines 41 and 52 in the reader). Removed the duplicates.

examples/C — @defgroup tutorial missing description

• pres_temp_4D_wr.c had @defgroup tutorial Tutorial Examples with the group description running into the file description. Added a blank line to separate them.

examples/C — typo

• filter_example.c line 124: "Storate" → "Storage".

examples/C — @author name

• All files attributed to Ed Hartnett were updated to use the full name "Edward Hartnett".