tox: add description (ansible-collections#1242)

tox: add description

Reviewed-by: Mark Chappell <None>

tox.ini

@@ -3,6 +3,7 @@ skipsdist=True
 envlist = clean,ansible{2.12,2.13}-py{38,39,310}-{with_constraints,without_constraints}
 
 [testenv]
+description = Run the test-suite and generate a HTML coverage report
 deps =
   pytest
   pytest-cov
@@ -20,8 +21,9 @@ skip_install = true
 commands = coverage erase
 
 [testenv:complexity-report]
+description = Generate a HTML complexity report in the complexity directory
 deps =
   # See: https://github.com/lordmauve/flake8-html/issues/30
   flake8>=3.3.0,<5.0.0'
   flake8-html
-commands = -flake8 --select C90 --max-complexity 10 --format=html --htmldir={posargs} plugins
+commands = -flake8 --select C90 --max-complexity 10 --format=html --htmldir={posargs:complexity} plugins