history.adoc: Remove PR478, reverted by PR549

.

* False change:  Period and hyphen in attribute names.
* Sentence was added, then removed later within same working version.

history.adoc

@@ -16,7 +16,6 @@
 * {issues}511[Issue #511]: Appendix B: New element in XML file header to record the "first published date"
 * {issues}509[Issue #509]: In exceptional cases allow a standard name to be aliased into two alternatives
 * {issues}501[Issue #501]: Clarify that data variables and variables containing coordinate data are highly recommended to have **`long_name`** or **`standard_name`** attributes, that **`cf_role`** is used only for discrete sampling geometries and UGRID mesh topologies, and that CF does not prohibit CF attributes from being used in ways that are not defined by CF but that in such cases their meaning is not defined by CF.
-* {issues}477[Issue #477]: Period and hyphen allowed in attribute names
 * {issues}500[Issue #500]: Appendix B: Added a **`conventions`** string to the standard name xml file format definition
 
 === Version 1.11 (05 December 2023)