public static List<AndroidVersion> getByLetter(String letter) {
		if (letter == null || letter.length() == 0) {
			return Collections.emptyList();
		}
		return getByLetter(letter.charAt(0));
	}
Returns an array of AndroidVersion's for the given version letter.
For example, Android 'M' applied to versions "6.0" and "6.0.1".
@param letter the Android version letter
@return the AndroidVersion for the given version letter
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/android/versions/AndroidVersionManager.java