Fix letters 'q' and 'z' not being in the dictionary

Enfore that all one-grams are present in the dictionary to make sure
it's possible to write any sentence

PoyoLang.Dictionary.Generation/Program.cs

@@ -56,7 +56,7 @@ Console.WriteLine("Computing ngrams");
 var ngrams = new Dictionary<string, long>();
 
 const int MaxLength = 8;
-const int MinLength = 1;
+const int MinLength = 2;
 
 foreach (var (word, frequency) in wordFrequencies)
 {
@@ -112,9 +112,15 @@ Console.WriteLine("Generating dictionary...");
 var dictionary = new Dictionary<string, string>();
 var ngramIndex = 0;
 
+// Prepend base letters to make sure all words are writeable
+string[] oneGrams = [
+    " ", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"
+];
+var fullNgrams = oneGrams.Concat(orderedNgrams.Select(p => p.Key)).ToArray();
+
 foreach (var letter in Alphabet.BaseAlphabet)
 {
-    dictionary[letter] = orderedNgrams[ngramIndex].Key;
+    dictionary[letter] = fullNgrams[ngramIndex];
 
     ngramIndex++;
 }