Section 11: A larger set of pre-release is higher

Clarifies the comparison between, eg 1.0.0-a vs 1.0.0-a.b

semver.md

@@ -99,8 +99,10 @@ numerically. Pre-release precedence MUST be determined by comparing each dot
 separated identifier as follows: identifiers consisting of only digits are 
 compared numerically and identifiers with letters or hyphens are compared 
 lexically in ASCII sort order. Numeric identifiers always have lower precedence
-than non-numeric identifiers. Example: 1.0.0-alpha < 1.0.0-alpha.1 < 
-1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.
+than non-numeric identifiers. A larger set of pre-release fields has a
+higher precedence than a smaller set, if all of the existing fields are
+equal. Example: 1.0.0-alpha < 1.0.0-alpha.beta < 1.0.0-alpha.1 <
+1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.
 
 Why Use Semantic Versioning?
 ----------------------------