[mail] documentation enhancement. (openhab#8177)

Signed-off-by: Gaël L'hopital <[email protected]>

bundles/org.openhab.binding.mail/README.md

@@ -88,16 +88,18 @@ sitemap demo label="Main Menu"
 This binding includes rule actions for sending email.
 Six different actions available:
 
-* `sendMail(String recipient, String subject, String text)`
-* `sendMail(String recipient, String subject, String text, String URL)`
-* `sendMail(String recipient, String subject, String text, List<String> URL)`
-* `sendHtmlMail(String recipient, String subject, String htmlContent)`
-* `sendHtmlMail(String recipient, String subject, String htmlContent, String URL)`
-* `sendHtmlMail(String recipient, String subject, String htmlContent, List<String> URL)`
+* `boolean success = sendMail(String recipient, String subject, String text)`
+* `boolean success = sendMail(String recipient, String subject, String text, String URL)`
+* `boolean success = sendMail(String recipient, String subject, String text, List<String> URL)`
+* `boolean success = sendHtmlMail(String recipient, String subject, String htmlContent)`
+* `boolean success = sendHtmlMail(String recipient, String subject, String htmlContent, String URL)`
+* `boolean success = sendHtmlMail(String recipient, String subject, String htmlContent, List<String> URL)`
 
 The `sendMail(...)` send a plain text mail (with attachments if supplied).
 The `sendHtmlMail(...)` send a HTML mail (with attachments if supplied).
 
+Both functions return a boolean as the result of the operation.
+
 `recipient` can be a single address (`[email protected]`) or a list of addresses, concatenated by a comma (`[email protected], [email protected]`).
 
 Since there is a separate rule action instance for each `smtp` thing, this needs to be retrieved through `getActions(scope, thingUID)`.
@@ -111,8 +113,8 @@ Examples:
 
 ```
 val mailActions = getActions("mail","mail:smtp:samplesmtp")
-mailActions.sendMail("[email protected]", "Test subject", "This is the mail content.")
-mailActions.sendMail("[email protected], [email protected]", "Test subject", "This is the mail content sent to multiple recipients.")
+val success = mailActions.sendMail("[email protected]", "Test subject", "This is the mail content.")
+success = mailActions.sendMail("[email protected], [email protected]", "Test subject", "This is the mail content sent to multiple recipients.")
 
 ```