Restrict colored_output value to always/never/auto.

docs/src/cdist-reference.rst.sh

@@ -369,9 +369,9 @@ CDIST_BETA
     Enable beta functionalities.
 
 CDIST_COLORED_OUTPUT
-    Use a colored output for different log levels.
-    It can be a boolean or 'auto' (default) which enables this feature if
-    stdout is a tty and disables it otherwise.
+    Colorize cdist's output. If enabled, cdist will use different colors for
+    different log levels.
+    Recognized values are 'always', 'never', and 'auto' (the default).
 
 CDIST_CACHE_PATH_PATTERN
     Custom cache path pattern.

docs/src/man1/cdist.rst

@@ -111,11 +111,11 @@ All commands accept the following options:
 **-h, --help**
     Show the help screen.
 
-**--colors COLORED_OUTPUT**
+**--colors WHEN**
     Colorize cdist's output. If enabled, cdist will use different colors for
     different log levels.
-    COLORED_OUTPUT recognizes the boolean values 'yes'/'no', 'on'/'off',
-    'true'/'false', '1'/'0', and 'auto' (the default).
+    COLORED_OUTPUT recognizes the values 'always', 'never',
+    and 'auto' (the default).
 
     If the value is 'auto', colored output is enabled if stdout is a TTY
     unless the NO_COLOR (https://no-color.org/) environment variable is defined.