Replace all non-alphanumerics in active help env var program prefix

There are other characters besides the dash that are fine in program
names, but are problematic in environment variable names. These include
(but are not limited to) period, space, and non-ASCII letters.

Author: scop

active_help.go

@@ -17,6 +17,7 @@ package cobra
 import (
 	"fmt"
 	"os"
+	"regexp"
 	"strings"
 )
 
@@ -29,6 +30,8 @@ const (
 	activeHelpGlobalDisable = "0"
 )
 
+var activeHelpEnvVarPrefixSubstRegexp = regexp.MustCompile(`[^A-Z0-9_]`)
+
 // AppendActiveHelp adds the specified string to the specified array to be used as ActiveHelp.
 // Such strings will be processed by the completion script and will be shown as ActiveHelp
 // to the user.
@@ -42,7 +45,7 @@ func AppendActiveHelp(compArray []string, activeHelpStr string) []string {
 
 // GetActiveHelpConfig returns the value of the ActiveHelp environment variable
 // <PROGRAM>_ACTIVE_HELP where <PROGRAM> is the name of the root command in upper
-// case, with all - replaced by _.
+// case, with all non-ASCII-alphanumeric characters replaced by `_`.
 // It will always return "0" if the global environment variable COBRA_ACTIVE_HELP
 // is set to "0".
 func GetActiveHelpConfig(cmd *Command) string {
@@ -55,9 +58,10 @@ func GetActiveHelpConfig(cmd *Command) string {
 
 // activeHelpEnvVar returns the name of the program-specific ActiveHelp environment
 // variable.  It has the format <PROGRAM>_ACTIVE_HELP where <PROGRAM> is the name of the
-// root command in upper case, with all - replaced by _.
+// root command in upper case, with all non-ASCII-alphanumeric characters replaced by `_`.
 func activeHelpEnvVar(name string) string {
 	// This format should not be changed: users will be using it explicitly.
 	activeHelpEnvVar := strings.ToUpper(fmt.Sprintf("%s%s", name, activeHelpEnvVarSuffix))
-	return strings.ReplaceAll(activeHelpEnvVar, "-", "_")
+	activeHelpEnvVar = activeHelpEnvVarPrefixSubstRegexp.ReplaceAllString(activeHelpEnvVar, "_")
+	return activeHelpEnvVar
 }

active_help.md

@@ -92,7 +92,7 @@ Allowing to configure Active Help is entirely optional; you can use Active Help
 
 The way to configure Active Help is to use the program's Active Help environment
 variable.  That variable is named `<PROGRAM>_ACTIVE_HELP` where `<PROGRAM>` is the name of your 
-program in uppercase with any `-` replaced by an `_`.  The variable should be set by the user to whatever
+program in uppercase with any non-ASCII-alphanumeric characters replaced by an `_`.  The variable should be set by the user to whatever
 Active Help configuration values are supported by the program.
 
 For example, say `helm` has chosen to support three levels for Active Help: `on`, `off`, `local`.  Then a user