This Pull Request is for HacktoberFest 2020

Description of Change

Checklist

• Added description

Description of Change

References

Checklist

Explain what you would like to see improved

After root-project/root#7399 we can now add RNTuple field descriptions to the output of RNTupleDescriptor::PrintInfo, as in TTree::Print().

Optional: share how it could be improved

Right now I think the most appropriate info category is `kStorageDetails

IEEE 754 recommends (but does not require) a compound function, which is in the process of being standardized for C and C++; we should expose it in swift-numerics. The simplest, most literal translation of the operation into Swift would be:

extension RealFunctions {
  /// (1+x)ⁿ
  /// 
  /// Returns NaN if x < -1.
  static func compound(_ x: Self, _ n: Int) -> Self {
    // not

The igraph tutorial (here online, source file here) should be reviewed:

• Is it up to date?
• Is it understandable by a newcomer?
• Are essential points unexplained or missing?

Ideally, this should be done by someone who is new to using igraph, to get a fresh perspective. Th