Markdown

There are automated checks for some of these rules. Run cargo xtask style-check to run them locally.

Formatting style

Use ATX-style headings (not Setext) with sentence case.
Do not use tabs; use only spaces.
Files must end with a newline.
Lines must not end with spaces. Double spaces have semantic meaning but can be invisible. Use a trailing backslash if you need a hard line break.
If possible, avoid double blank lines.
Do not wrap long lines. This helps with reviewing diffs of the source.
Use smart punctuation instead of Unicode characters. For example, use --- for an em dash instead of the Unicode character. Characters such as the em dash can be difficult to see in a fixed-width editor, and some editors may not have easy methods to enter such characters.
See Admonitions for formatting callouts such as notes, edition differences, and warnings.

Do not use indented code blocks; use fenced code blocks with 3+ backticks instead.
Code blocks should have an explicit language tag.

See Links for more information about linking.

Links to other chapters should be relative and use the .md extension.
Links to other rust-lang books that are published with the Reference should also be relative so that the linkchecker can validate them. See outside book links.
Links to the standard library should use rustdoc-style links as described in standard library links.
Prefer reference links, with shortcut reference links where appropriate. Place sorted link reference definitions at the bottom of the file, or at the bottom of a section if there is an unusually large number of links specific to that section.
```
Example of shortcut link: [enumerations]
Example of reference link with label: [block expression][block]

[block]: expressions/block-expr.md
[enumerations]: types/enum.md
```