- completed section on built-in functions

- moved Conversions section out of built-in functions and into expressions
- fixed syntax of conversions (parens are not mandatory if the type is not a TypeName)
  (this is the only change to the Conversions section; the rest of the text is just moved;
  old line: 4043, new line: 3078)
- fixed syntax of composite literals (parens are allowed around LiteralType)

DELTA=239  (115 added, 98 deleted, 26 changed)
OCL=35118
CL=35159