DOC: Update naming convention in contributors guide: separate words in parameter names by underscores (#4284)

Co-authored-by: Dongdong Tian <seisman.info@gmail.com>
Co-authored-by: Michael Grund <23025878+michaelgrund@users.noreply.github.com>

Author: 3 people

doc/contributing.md

@@ -488,10 +488,10 @@ integration systems will warn us and you can make a new commit with the formatte
 Even better, you can just write `/format` in the first line of any comment in a
 pull request to lint the code automatically.
 
-When wrapping a new alias, use an underscore to separate words bridged by vowels
-(aeiou), such as `no_skip` and `z_only`. Do not use an underscore to separate
-words bridged only by consonants, such as `distcalc`, and `crossprofile`. This
-convention is not applied by the code checking tools, but the PyGMT maintainers
+When introducing a new parameter name, use an underscore to separate words. This improves
+readability and aligns with the [PEP 8 style guide](https://peps.python.org/pep-0008/).
+For common shortcuts no underscore is needed, e.g., `surftype`, `outgrid`, or `timefmt`.
+This convention is not applied by the code checking tools, but the PyGMT maintainers
 will comment on any pull requests as needed.
 
 When working on a tutorial or a gallery plot, it is good practice to use code