patch 8.0.1787: cannot insert the whole cursor line

Problem:    Cannot insert the whole cursor line.
Solution:   Make CTRL-R CTRL-L work. (Andy Massimino, closes #2857)
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 64914aa..0124098 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -3299,7 +3299,8 @@
     /* check for valid regname; also accept special characters for CTRL-R in
      * the command line */
     if (regname != Ctrl_F && regname != Ctrl_P && regname != Ctrl_W
-	    && regname != Ctrl_A && !valid_yank_reg(regname, FALSE))
+	    && regname != Ctrl_A && regname != Ctrl_L
+	    && !valid_yank_reg(regname, FALSE))
 	return FAIL;
 
     /* A register containing CTRL-R can cause an endless loop.  Allow using