Updated standard names issue template.

Author: japamment

.github/ISSUE_TEMPLATE/standard-name-template.md

@@ -10,7 +10,7 @@ assignees: ''
 
 Before submitting an issue be sure you have read and understood the rules for vocabulary changes: http://cfconventions.org/standard_name_rules.html
 
-Change proposals should include the following information as applicable.
+Please note that it is fine to group together a number of proposals in a single GitHub issue (i.e. it is not necessary to open a separate issue for each vocabulary term). Change proposals should include the following information as applicable.
 
 **Proposer's name** This information will be used to add entries to the vocabulary editor: http://cfeditor.ceda.ac.uk/proposals/1. If you prefer not to add your name, your github id will be used instead.
 **Date** Also used in the vocabulary editor.