bug#10841: 24.0.92; Add field text property to ERC prompt

[Deniz Dogan]

Attached is a patch which adds the field text property to the ERC
prompt.  This allows users to use `kill-whole-line' to kill all text
back to the prompt given that it's on a single line.

=== modified file 'lisp/erc/erc.el'
--- lisp/erc/erc.el     2012-01-19 07:21:25 +0000
+++ lisp/erc/erc.el     2012-02-18 20:50:44 +0000
@@ -3646,6 +3646,7 @@
                                     'start-open t ; XEmacs
                                     'rear-nonsticky t ; Emacs
                                     'erc-prompt t
+                                    'field t
                                     'front-sticky t
                                     'read-only t))
        (erc-put-text-property 0 (1- (length prompt))