docs: simplify docs for parser.result

[golopot]

Implementation of Parsimmon.result:

parsimmon/src/parsimmon.js

Lines 959 to 963 in f71a738

	_.result = function(res) {
	return this.map(function() {
	return res;
	});
	};

[coveralls]

Coverage remained the same at 100.0% when pulling 1efbdfc on golopot:patch-1 into f71a738 on jneen:master.

[wavebeem]

I appreciate the PR, but this is not actually 100% interchangeable