dselect(1): Rename USAGE section to ACTIONS

Document the ways actions can be performed, either interactively or from
the command line.

debian/changelog

@@ -119,6 +119,9 @@ dpkg (1.16.1) UNRELEASED; urgency=low
   * Do not require programs to define thisname, provide two new functions
     to handle the program name (dpkg_set_progname and dpkg_get_progname).
     Closes: #631757
+  * Man pages cleanup:
+    - Rename “USAGE” dselect(1) section to “ACTIONS” and clarify they can
+      be performed interactively or from command line.
 
   [ Bill Allombert]
   * Add support for Build-Features: build-arch. Closes: #229357

man/dselect.1

@@ -125,11 +125,12 @@ Print a brief help text and exit successfully.
 .B \-\-version
 Print version information and exit successfully.
 .
-.SH USAGE
+.SH ACTIONS
 When
 .B dselect
-is started interactively, it prompts the user with a menu of available
-actions:
+is started it can perform the following actions, either directly if it
+was specified on the command line or by prompting the user with a menu
+of available actions if running interactively:
 .SS access
 Choose and configure an access method to access package repositories.
 .sp