Issue #17203: add long option names to unittest discovery docs.

Doc/library/unittest.rst

@@ -263,15 +263,15 @@ The ``discover`` sub-command has the following options:
 
    Verbose output
 
-.. cmdoption:: -s directory
+.. cmdoption:: -s, --start-directory directory
 
    Directory to start discovery (``.`` default)
 
-.. cmdoption:: -p pattern
+.. cmdoption:: -p, --pattern pattern
 
    Pattern to match test files (``test*.py`` default)
 
-.. cmdoption:: -t directory
+.. cmdoption:: -t, --top-level-directory directory
 
    Top level directory of project (defaults to start directory)
 

Misc/NEWS

@@ -748,6 +748,8 @@ Tools/Demos
 Documentation
 -------------
 
+- Issue #17203: add long option names to unittest discovery docs.
+
 - Issue #13094: add "Why do lambdas defined in a loop with different values
   all return the same result?" programming FAQ.