Given following log snippets, their explanation, and nothing else, explain what failure, if any, occurred during build of this package.

  Snippets are in a format of [X] : [Y], where [X] is a log snippet, and [Y] is the explanation.

  Snippets are delimited with '================'.

  Drawing on information from all snippets, provide a concise explanation of the issue and recommend a solution.

  Explanation of the issue, and recommended solution, should take a handful of sentences.

  Snippets:

  [    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)]: [File `/usr/share/gems/gems/rdoc-6.8.0/lib/rdoc/generator/template/darkfish/_sidebar_toggle.rhtml` is not present, causing error.]
=============
[ERROR:  While executing gem ... (RDoc::Error)]: [Error encountered while executing RDoc.]

Issue: Expected file `/usr/share/gems/gems/rdoc-6.8.0/lib/rdoc/generator/template/darkfish/_sidebar_toggle.rhtml` is not present. Causing failure during documentation build.

This is probably due to incorrectly installed, or missing`rdoc-6.8.0` gem, which is supposed to provide it.
Resolution: Ensure that the `rdoc` package is properly installed and verified before build. 