[css-values-3] Tidy bracket range definition

- Fix incorrect heading level & a typo from
  8ea8d7d
- Add examples converting the notation to prose.

Author: AmeliaBR

css-values-3/Overview.bs

@@ -681,12 +681,12 @@ Numeric Data Types</h2>
 	and various <a>dimensions</a>
 	including <<length>>, <<angle>>, <<time>>, <<frequency>>, and <<resolution>>.
 
-	Note: While genera-purpose <a>dimensions</a> are defined here,
+	Note: While general-purpose <a>dimensions</a> are defined here,
 	some other modules define additional data types
 	(e.g. [[css-grid-1]] introduces ''fr'' units)
 	whose usage is more localized.
 
-<h2 id="numeric-ranges">
+<h3 id="numeric-ranges">
 Range Restrictions and Range Definition Notation</h3>
 
 	Properties can restrict numeric values to some range.
@@ -698,8 +698,8 @@ Range Restrictions and Range Definition Notation</h3>
 	<code>[<var>min</var>,<var>max</var>]</code>
 	within the angle brackets, after the identifying keyword,
 	indicating a closed range
-	between (and including) <var>min</var> and <var>max</var>,
-	e.g. <<integer [0,10]>>.
+	between (and including) <var>min</var> and <var>max</var>.
+	For example, <<integer [0,10]>> indicates an integer between 0 and 10, inclusive.
 
 	Note: CSS values generally do not allow open ranges;
 	thus only square-bracket notation is used.
@@ -709,6 +709,7 @@ Range Restrictions and Range Definition Notation</h3>
 	UAs should support reasonably useful ranges and precisions.
 	Range extremes that are ideally unlimited
 	are indicated using &infin; or &minus;&infin; as appropriate.
+	For example, <<length [0, &infin;]>> indicates a non-negative length.
 
 	If no range is indicated,
 	either by using the <a>bracketed range notation</a>