Number type suffixes table added
Number type suffixes example added
Underscore in literal added
Underscore in literal added
Hexadecimal literal added
Examples improved
Octal literal added.
Number type suffixes improved
Merge pull request #235 from bura/doc-core-syntax

GROOVY-6268: Numbers section
GROOVY-6268: minor tweak to the number section
Non-needed FQN since Big(Decimal|Integer) are imported by default in Groovy
GROOVY-6268: some clarifications on booleans
GROOVY-6268: Documented type coercion
   * closure to SAM type
   * closure to any type
   * implicit closure coercion
   * map to type
   * as vs asType