patch 8.2.3750: error messages are everywhere

Problem:    Error messages are everywhere.
Solution:   Move more error messages to errors.h and adjust the names.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 1fc538b..4d739f9 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -9167,7 +9167,7 @@
 	case SPEC_SID:
 		if (current_sctx.sc_sid <= 0)
 		{
-		    *errormsg = _(e_usingsid);
+		    *errormsg = _(e_using_sid_not_in_script_context);
 		    return NULL;
 		}
 		sprintf((char *)strbuf, "<SNR>%d_", current_sctx.sc_sid);