patch 8.0.1295: cannot automatically get a server name in a terminal

Problem:    Cannot automatically get a server name in a terminal.
Solution:   Add the --enable-autoservername flag to configure. (Cimbali,
            closes #2317)
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index f2abcbd..f754892 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -8820,6 +8820,7 @@
 arabic			Compiled with Arabic support |Arabic|.
 arp			Compiled with ARP support (Amiga).
 autocmd			Compiled with autocommand support. |autocommand|
+autoservername		Automatically enable |clientserver|
 balloon_eval		Compiled with |balloon-eval| support.
 balloon_multiline	GUI supports multiline balloons.
 beos			BeOS version of Vim.