Contributing: clarify hard-wrapping and code sample line length

CONTRIBUTING.md

@@ -124,7 +124,9 @@ Use the following conventions when creating a page:
 - The HTML filename and MD filename should match exactly except for the file extension.
 - The filenames should closely match the title of the page, including words like "and" and "the", but should be in all lowercase with hyphens instead of spaces and punctuation. For example, `cash-a-check-for-an-exact-amount.md`. If you change the title of a page, change the filename too. (If it has already been published at another URL, leave a redirect from the old URL.)
 - Always start a page with a h1 header.
-- Don't use any formatting (like _italics_ or `code font`) in the title of the page
+- Don't use any formatting (like _italics_ or `code font`) in the title of the page.
+- Don't hard-wrap text in Markdown files.
+- For code samples, try to keep lines no longer than 80 columns wide.
 - When in doubt, follow [Ciro Santilli's Markdown Style Guide (Writability Profile)](https://cirosantilli.com/markdown-style-guide/).
 - Landing pages should be in subfolders and should have the same filename as the folder. For example, the landing page of the "Accounts" page group should be `accounts/accounts.md` with the HTML filename `accounts.html`. **Don't** use `index.md`.
 - Don't use tab characters for indentation in Markdown or code samples. Use **4 spaces per indent**, except in **JavaScript** code samples, which should use 2 spaces per indent.