Adds documentation for encode/decode functions

Sources/Geoflash/Geoflash+Decode.swift

@@ -54,6 +54,19 @@ extension Geoflash {
 
     }
 
+    /// Decodes a [Geohash](https://en.wikipedia.org/wiki/Geohash) encoded string
+    ///
+    /// To be a valid Geohash the `String` passed must contain any digits 0-9 and any lower case
+    /// digit in the set `bcdefghjkmnpqrstuvwxyz`. This is the English language alphabet, excluding
+    /// the letters `a`, `i`, `l` and `o`
+    ///
+    /// - Parameter geohash: The `String` value to attempt to decode.
+    /// - Parameter maxPointDistance: A `Double` value representing the number of decimal places.
+    ///
+    /// - Returns: An array of [GeoJSON](https://datatracker.ietf.org/doc/html/rfc7946)
+    /// encoded coordinates.
+    ///
+    /// - Throws: When passed an invalid geohash.
     public static func decode(
         geohash: String,
         maxPointDistance: Double = 0.000001

Sources/Geoflash/Geoflash+Encode.swift

@@ -6,6 +6,15 @@ extension Geoflash {
     static let lng = Geoflash.Range(min: -180.0, max: 180.0)!
     static let validPrecisions = 1...12
 
+    /// Encode latitude/longitude as [Geohash](https://en.wikipedia.org/wiki/Geohash)
+    ///
+    /// - Parameter latitude: The latitude to be encoded (-90...90 valid values).
+    /// - Parameter longitude: The longitude to be encoded (-180...180 valid values).
+    /// - Parameter precision: The count of characters to be included in the result (1...12 valid).
+    ///
+    /// - Returns: The Geohash encoded string.
+    ///
+    /// - Throws: On invalid arguments.
     public static func encode(
         latitude: Double,
         longitude: Double,