Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
error generating index.html: No such file or directory @ rb_sysopen - /usr/share/gems/gems/rdoc-6.8.0/lib/rdoc/generator/template/darkfish/_sidebar_toggle.rhtml (RDoc::Error)

The core issue seems to be a missing file: /usr/share/gems/gems/rdoc-6.8.0/lib/rdoc/generator/template/darkfish/_sidebar_toggle.rhtml. This file is a template used by RDoc to generate the sidebar toggle element in the documentation.