fix: tweak config set messages

Author: jshackell-sfdc

messages/config.set.md

@@ -6,7 +6,7 @@ Set one or more configuration variables, such as your default org.
 
 Use configuration variables to set CLI defaults, such as your default org or the API version you want the CLI to use. For example, if you set the "target-org" configuration variable, you don't need to specify it as a "sf deploy metadata" flag if you're deploying to your default org.
 
-Local configuration variables apply only to your current project. Global variables, specified with the --global flag, apply in any directory.
+Local configuration variables apply only to your current project. Global variables, specified with the --global flag, apply in any Salesforce DX project.
 
 The resolution order if you've set a flag value in multiple ways is as follows:
 
@@ -30,17 +30,18 @@ Run "sf config list" to see the configuration variables you've already set and t
 
   <%= config.bin %> <%= command.id %> --global target-org=my-scratch-org
 
-- Single config values can be set without an equal sign
+- Set a single configuration variable without using an equal sign; this syntax doesn't work when setting multiple configuration variables:
+
   <%= config.bin %> <%= command.id %> target-org me@my.com
 
 # flags.global.summary
 
-Set the configuration variables globally, so they can be used from any directory.
+Set the configuration variables globally, so they can be used from any Salesforce DX project.
 
 # error.ArgumentsRequired
 
 You must provide one or more configuration variables to set. Use the --help flag to view the available configuration variables.
 
 # error.ValueRequired
 
-You must provide a value when setting a config. Use `sf config unset the-config-name` to remove existing configs.
+You must provide a value when setting a config. Use `sf config unset the-config-name` to unset existing configs.