message: [docs] Update developer notes to discourage very long lines
diff: @@ -75,6 +75,11 @@ tool to clean up patches automatically before submission.
  on the same line as the `if`, without braces. In every other case,
  braces are required, and the `then` and `else` clauses must appear
  correctly indented on a new line.
  + - There's no hard limit on line width, but prefer to keep lines to <100
  + characters if doing so does not decrease readability. Break up long
  + function declarations over multiple lines using the Clang Format
  + [AlignAfterOpenBracket](https://clang.llvm.org/docs/ClangFormatStyleOptions.html)
  + style option.
  - **Symbol naming conventions**. These are preferred in new code, but are not
  required when doing so would need changes to significant pieces of existing
  