Fix README missing message and docstring typos

Author: gregjkal

libraries/constants.py

@@ -348,7 +348,7 @@
 
 # This constant is for library-versions missing a README
 README_MISSING = (
-    "⚠️ This library has no README.md or library-details.adoc; "
+    "⚠️ This library has no README file or library-detail.adoc; "
     "consider contributing one."
 )
 

libraries/models.py

@@ -335,9 +335,9 @@ def save(self, *args, **kwargs):
     def get_description(self, client, tag="develop"):
         """Get description from the appropriate file on GitHub.
 
-        For more recent versions, that will be `/doc/library-details.adoc`.
+        For more recent versions, that will be `/doc/library-detail.adoc`.
         For older versions, or libraries that have not adopted the adoc file,
-        that will be `/README.md`.
+        that will be `/README.md` or `/README.adoc`.
         """
         content = None
         # File paths/names where description data might be stored.