CONTRIBUTING: updated and added copyright info

CONTRIBUTING

@@ -90,8 +90,9 @@ notice:
  *     USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-When writing code, make sure lines never exceed 80 characters in width when
-using four-character-wide indentation steps.
+Make sure lines never exceed 80 characters in width when using
+four-character-wide indentation steps. This helps contributors who do not have
+text wrapping in their text editors.
 
 For usage text and help messages, please do not implement a -h option. Just
 print usage information when any erroneous option is specified. Follow the
@@ -100,16 +101,31 @@ NetBSD style guide for usage text output format [1].
 If committing a new source file for a utility, format the commit message like
 this:
 
-$ git commit -m 'tool(1): <information>'
+$ git commit -m 'tool(1): added feature x'
 
 If committing a new library or header file:
 
-$ git commit -m 'library(1): <information>'
+$ git commit -m 'library(3): fixed overflow'
+$ git commit -m 'header.h(3): added header.h(3)'
+
+If committing a new manual page:
+
+$ git commit -m 'tool.1: added author details'
 
 If modifying some other file or directory:
 
 $ git commit -m 'README: clarification'
-$ git commit -m 'tests: posix: fixed bug #47'
-$ git commit -m 'docs: tool(1): added author information'
+$ git commit -m 'tests/posix: fixed bug #47'
 
-etc.
+For multiple of these:
+
+$ git commit -m 'Makefile, tool(1): added tool(1)'
+$ git commit -m 'tool(1): added tool(1); \
+	library(3), library.3: added library(3)'
+
+
+[1] http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style
+
+--
+This work © 2023–2024 by Emma Tebibyte is licensed under CC BY-SA 4.0. To view a
+copy of this license, visit <http://creativecommons.org/licenses/by-sa/4.0/>