Add a style guide for the docs (#323)

docs/README.md

@@ -2,6 +2,8 @@
 
 This directory contains the documentation for Maud.
 
+It is hosted at <https://maud.lambda.xyz>.
+
 ## Build
 
 Build the documentation:
@@ -14,6 +16,18 @@ You can also delete the build artifacts with:
 
     make clean
 
+## Style
+
+- [Be brief][short].
+- Use [semantic line breaks][sembr].
+- American spelling.
+- Parentheticals should use spaced en dashes –
+  like this –
+  not em dashes.
+
+[short]: https://developers.google.com/tech-writing/one/short-sentences
+[sembr]: https://sembr.org/
+
 ## Watch
 
 To ease editing,

docs/content/elements-attributes.md

@@ -89,9 +89,10 @@ html! {
 
 ## Optional attributes: `title=[Some("value")]`
 
-Add optional attributes to an element using `attr=[value]` syntax, with *square*
+Add optional attributes to an element using `attr=[value]` syntax,
-brackets. These are only rendered if the value is `Some<T>`, and entirely
+with *square* brackets.
-omitted if the value is `None`.
+These are only rendered if the value is `Some<T>`,
+and entirely omitted if the value is `None`.
 
 ```rust
 # let _ = maud::

docs/content/web-frameworks.md

@@ -118,8 +118,10 @@ maud = { version = "*", features = ["tide"] }
 # ...
 ```
 
-This adds an implementation of `From<PreEscaped<String>>` for the `Response` struct.
+This adds an implementation of `From<PreEscaped<String>>`
-Once provided, callers may return results of `html!` directly as responses:
+for the `Response` struct.
+Once provided,
+callers may return results of `html!` directly as responses:
 
 ```rust,no_run
 use maud::html;