[DOC] Add `or nil` to call-seq [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66695 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

complex.c

@@ -419,7 +419,7 @@ static VALUE nucomp_s_convert(int argc, VALUE *argv, VALUE klass);
 
 /*
  * call-seq:
- *    Complex(x[, y], exception: false)  ->  numeric
+ *    Complex(x[, y], exception: false)  ->  numeric or nil
  *
  * Returns x+i*y;
  *

object.c

@@ -3221,7 +3221,7 @@ opts_exception_p(VALUE opts)
 
 /*
  *  call-seq:
- *     Integer(arg, base=0, exception: true)    -> integer
+ *     Integer(arg, base=0, exception: true)    -> integer or nil
  *
  *  Converts <i>arg</i> to an <code>Integer</code>.
  *  Numeric types are converted directly (with floating point numbers
@@ -3583,7 +3583,7 @@ rb_Float(VALUE val)
 
 /*
  *  call-seq:
- *     Float(arg, exception: true)    -> float
+ *     Float(arg, exception: true)    -> float or nil
  *
  *  Returns <i>arg</i> converted to a float. Numeric types are converted
  *  directly, and with exception to string and nil the rest are converted using <i>arg</i>.to_f.

rational.c

@@ -529,8 +529,8 @@ static VALUE nurat_s_convert(int argc, VALUE *argv, VALUE klass);
 
 /*
  * call-seq:
- *    Rational(x, y, exception: true)  ->  rational
- *    Rational(arg, exception: true)   ->  rational
+ *    Rational(x, y, exception: true)  ->  rational or nil
+ *    Rational(arg, exception: true)   ->  rational or nil
  *
  * Returns +x/y+ or +arg+ as a Rational.
  *