Arduino library creation - Calling library and Merging
If you consult the Arduino Library Specification's section on keywords.txt:


  A tab should be used to separate each name from the KEYWORD1/Keyword2/Literal1 identifier.


A true tab character is required, rather than spaces, as you have in your keywords.txt. It is common for text editors to be configured to add a given number of spaces when the tab key is pressed rather than a true tab character. That's great but in this case you will need to be sure that the tab character is used.

Note that the tab requirement will be relaxed in the Arduino IDE 1.9.0 release, which will also accept space(s) as a keywords separator but it's still best to use tabs for backwards compatibility since people will be using pre-1.9.0 IDE versions for years to come.