Tweak docstring of cider-docstring--format and remove redundant comment

cider-docstring.el

@@ -148,10 +148,14 @@ Prioritize rendering as much as possible while staying within `cider-docstring-m
     (concat string (when (> (length lines) max-lines) "..."))))
 
 (defun cider-docstring--format (string)
-  "Return a nicely formatted STRING to be displayed to the user."
-  ;; As this is a literal docstring from the source code and
-  ;; there are two spaces at the beginning of lines in docstrings,
-  ;; we remove them to make it align nicely when it is displayed.
+  "Return a nicely formatted STRING to be displayed to the user.
+
+We need to format the docstring before displaying it to the user
+because it is obtained from the source code.  For example, this means
+that it usually has two spaces before each line used for indentation
+\(see https://guide.clojure.style/#docstring-indentation).  While displaying
+the docstring to the user, we usually want to control indentation and
+other aspects of the presentation, so we format it before displaying."
   (replace-regexp-in-string "\n  " "\n" string))
 
 (provide 'cider-docstring)