patch 8.2.3069: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move some error messages to errors.h.  Use clearer names.
diff --git a/src/userfunc.c b/src/userfunc.c
index 4756bf9..06fca0c 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -4864,7 +4864,7 @@
 	    {
 		// If the function deleted lines or switched to another buffer
 		// the line number may become invalid.
-		emsg(_(e_invrange));
+		emsg(_(e_invalid_range));
 		break;
 	    }
 	    curwin->w_cursor.lnum = lnum;