Correct formatting in history.adoc

history.adoc

@@ -7,8 +7,8 @@
 
 === Working version (most recent first)
 
-* {issues}542{Issue #542}: Clarify and rearrange text of section 4.4 about time coordinate units and calendars; introduce new text and a diagram explaining leap-seconds in existing calendars; define leap_second keyword of units_metadata attribute; define utc and tai calendars; define "datetime" in section 1.3.
-* {issues}166{Issue #166}: Clarify that time coordinate variables must have **`units`** containing **`since`** and a reference time; distinguish between canonical units of time with and without **`since`**.
+* {issues}542[Issue #542]: Clarify and rearrange text of section 4.4 about time coordinate units and calendars; introduce new text and a diagram explaining leap-seconds in existing calendars; define leap_second keyword of units_metadata attribute; define utc and tai calendars; define "datetime" in section 1.3.
+* {issues}166[Issue #166]: Clarify that time coordinate variables must have **`units`** containing **`since`** and a reference time; distinguish between canonical units of time with and without **`since`**.
 * {issues}141[Issue #141]: Clarification that text may be stored in variables and attributes as either vlen strings or char arrays, and must be represented in Unicode Normalization Form C and encoded according to UTF-8.
 * {issues}367[Issue #367]: Remove the AMIP and GRIB columns from the standard name table format defined by Appendix B.
 * {issues}403[Issue #403]: Metadata to encode quantization properties