patch 8.2.1544: cannot translate messages in a Vim script

Problem:    Cannot translate messages in a Vim script.
Solution:   Add gettext().  Try it out for a few messages in the options
            window.
diff --git a/src/po/README.txt b/src/po/README.txt
index e60d1d2..68d267a 100644
--- a/src/po/README.txt
+++ b/src/po/README.txt
@@ -78,7 +78,8 @@
 
 (2) Translate
     See the gettext documentation on how to do this.  You can also find
-    examples in the other po files.
+    examples in the other po files.  You can use "gF" on the file name to see
+    the context of the message.
     Search the po file for items that require translation:
 
 	/fuzzy\|^msgstr ""\(\n"\)\@!
@@ -123,6 +124,13 @@
 
     Look out for syntax errors and fix them.
 
+(6) Local tryout:
+    Vim normally picks up the .mo files from:
+	    $VIMRUNTIME/lang/{lang}/LC_MESSAGES/vim.mo
+    To try out the messages with Vim use:
+    	    make tryoutinstall
+    And run Vim with $VIMRUNTIME set to ../runtime
+
 
 USING GETTEXT WITHOUT ICONV