Improve docstrings and NEWS item of 'repeat-mode'

* lisp/repeat.el (repeat-exit-timeout, repeat-echo-function)
(repeat-in-progress, repeat-map): Update docstrings.

etc/NEWS

@@ -3219,21 +3219,22 @@ batch mode.
 * New Modes and Packages in Emacs 28.1
 
 +++
-** New transient mode 'repeat-mode' to allow shorter key sequences.
+** New mode 'repeat-mode' to allow shorter key sequences.
 Type 'M-x repeat-mode RET' to enable this mode.  You can then type
 'C-x u u' instead of 'C-x u C-x u' to undo many changes, 'C-x o o'
 instead of 'C-x o C-x o' to switch windows, 'C-x { { } } ^ ^ v v' to
 resize the selected window interactively, 'M-g n n p p' to navigate
-next-error matches.  Any other key exits repeat mode and then is
+next-error matches.  Any other key exits this temporarily enabled
-executed normally.  'repeat-exit-key' defines an additional key to
+transient mode that supports shorter keys, and then after exiting
-exit mode like 'isearch-exit' ('RET').  The user option
+from this mode the default key binding is used for the last typed key.
-'repeat-exit-timeout' specifies the number of seconds of idle time to
+'repeat-exit-key' defines an additional key to exit mode like
-break the repetition chain automatically.  With 'repeat-keep-prefix'
+'isearch-exit' ('RET').  The user option 'repeat-exit-timeout'
-you can keep the prefix arg of the previous command.  For example,
+specifies the number of seconds of idle time to break the repetition
-this can help to reverse the window navigation direction with
+chain automatically.  With 'repeat-keep-prefix' you can keep the
-e.g. 'C-x o M-- o o'.  Also it can help to set a new step with
+prefix arg of the previous command.  For example, this can help to
-e.g. 'C-x { C-5 { { {', which will set the window resizing step to 5
+reverse the window navigation direction with e.g. 'C-x o M-- o o'.
-columns.
+Also it can help to set a new step with e.g. 'C-x { C-5 { { {',
+which will set the window resizing step to 5 columns.
 
 ---
 ** New themes 'modus-vivendi' and 'modus-operandi'.

lisp/repeat.el

@@ -344,8 +344,8 @@ For example, you can set it to <return> like `isearch-exit'."
 
 (defcustom repeat-exit-timeout nil
   "Break the repetition chain of keys after specified timeout.
-When a number, exit the repeat mode after idle time of the specified
+When a number, exit the transient repeating mode after idle time
-number of seconds."
+of the specified number of seconds."
   :type '(choice (const :tag "No timeout to exit repeating sequence" nil)
                  (number :tag "Timeout in seconds to exit repeating"))
   :group 'convenience
@@ -363,7 +363,7 @@ number of seconds."
 (defcustom repeat-echo-function #'repeat-echo-message
   "Function to display a hint about available keys.
 Function is called after every repeatable command with one argument:
-a repeating map, or nil after deactivating the repeat mode."
+a repeating map, or nil after deactivating the transient repeating mode."
   :type '(choice (const :tag "Show hints in the echo area"
                         repeat-echo-message)
                  (const :tag "Show indicator in the mode line"
@@ -374,11 +374,11 @@ a repeating map, or nil after deactivating the repeat mode."
   :version "28.1")
 
 (defvar repeat-in-progress nil
-  "Non-nil when the repeating map is active.")
+  "Non-nil when the repeating transient map is active.")
 
 ;;;###autoload
 (defvar repeat-map nil
-  "The value of the repeating map for the next command.
+  "The value of the repeating transient map for the next command.
 A command called from the map can set it again to the same map when
 the map can't be set on the command symbol property `repeat-map'.")