Changes
If not categorising, output a space instead of nothing to prevent unwanted blank lines; see edit request on talk page
{{#ifeq:{{FULLROOTPAGENAME}}|Wikipedia:Template messages| <!--Do not categorize;   prevents blank line if template is only thing on the line-->|<!--
-->{{#ifexpr:{{#if:{{NAMESPACE}}|0|1}}+{{#ifeq:{{{onlyarticles|no}}}|yes|0|1}}
|{{#if:{{{3|}}}
-->}}{{#if:{{{4|}}}
|[[Category:{{{4}}}]]}}<!--
-->| <!--  prevents blank line if template is only thing on the line-->}}<!--
-->}}<noinclude>
{{documentation}}
</noinclude>
