title: .Rmd posts do not render in Blogdown using 'wowchemy/starter-academic' in multilingual configuration
body: <p>I installed via Rstudio a Blogdown using 'wowchemy/starter-academic' theme (aka hugo-academic).
  I changed to put the multilingual configuration in <code>language.tom</code>.
  And I put the initial folders <code>home</code> and <code>post</code> in the folders <code>content/en</code> and <code>content/es</code></p>
  <pre><code>[en]
    languageCode = &quot;en-us&quot;
    contentDir = &quot;content/en&quot;  # Uncomment for multi-lingual sites, and move English content into `en` sub-folder.
  
  # Uncomment the lines below to configure your website in a second language.
  [es]
    languageCode = &quot;es-ES&quot;
    contentDir = &quot;content/es&quot;
  </code></pre>
  <p>However, I use the addin <code>blogdown:::serve_site()</code> to render the site but I obtain systematically this error for the <code>.Rmd</code> posts:</p>
  <pre><code>WARN 2020/12/01 20:25:25 Alert shortcode will be deprecated in future. Use Callout instead. Rename `alert` to `callout` in &quot;post/writing-technical-content/index.md&quot;
  
  ERROR 2020/12/01 20:25:25 [en] REF_NOT_FOUND: Ref &quot;en/post/2015-07-23-r-rmarkdown/index.html&quot;: &quot;/Users/fabio/Desktop/BLog/Test 3 blogdown/content/en/post/2015-07-23-r-rmarkdown/index.html:9:14&quot;: page not found
  </code></pre>
  <p>I tested to the options: <a href="https://stackoverflow.com/questions/50077412/">In R 3.5 blogdown:::serve_site() cannot render .Rmd file</a></p>
  <p>Maybe I am missing something, any help is really appreciated
  Thanks @Yihui anyway for the great rmarkdown and blogdown package</p>
  <p>my configuration:
  HUGO_VERSION = &quot;0.79.0&quot;</p>
  <pre><code>─ Session info ──────────────────────────────────────────────────────────────────────────────────
   setting  value                       
   version  R version 4.0.2 (2020-06-22)
   os       macOS Catalina 10.15.7      
   system   x86_64, darwin17.0          
   ui       RStudio                     
   language (EN)                        
   collate  en_US.UTF-8                 
   ctype    en_US.UTF-8                 
   tz       Europe/Paris                
   date     2020-12-01                  
  
  ─ Packages ──────────────────────────────────────────────────────────────────────────────────────
   package   * version  date       lib source                            
   base64enc   0.1-3    2015-07-28 [1] CRAN (R 4.0.0)                    
   BH          1.72.0-3 2020-01-08 [1] CRAN (R 4.0.0)                    
   blogdown    0.21.48  2020-12-01 [1] Github (rstudio/blogdown@ece8b58) 
   bookdown    0.21     2020-10-13 [1] CRAN (R 4.0.2)                    
   digest      0.6.27   2020-10-24 [1] CRAN (R 4.0.2)                    
   evaluate    0.14     2019-05-28 [1] CRAN (R 4.0.0)                    
   glue        1.4.2    2020-08-27 [1] CRAN (R 4.0.2)                    
   highr       0.8      2019-03-20 [1] CRAN (R 4.0.0)                    
   htmltools   0.5.0    2020-06-16 [1] CRAN (R 4.0.0)                    
   httpuv      1.5.4    2020-06-06 [1] CRAN (R 4.0.0)                    
   jsonlite    1.7.1    2020-09-07 [1] CRAN (R 4.0.0)                    
   knitr       1.30     2020-09-22 [1] CRAN (R 4.0.2)                    
   later       1.1.0.1  2020-06-05 [1] CRAN (R 4.0.0)                    
   magrittr    2.0.1    2020-11-17 [1] CRAN (R 4.0.2)                    
   markdown    1.1      2019-08-07 [1] CRAN (R 4.0.0)                    
   mime        0.9      2020-02-04 [1] CRAN (R 4.0.0)                    
   promises    1.1.1    2020-06-09 [1] CRAN (R 4.0.0)                    
   R6          2.5.0    2020-10-28 [1] CRAN (R 4.0.2)                    
   Rcpp        1.0.5    2020-07-06 [1] CRAN (R 4.0.0)                    
   rlang       0.4.9    2020-11-26 [1] CRAN (R 4.0.2)                    
   rmarkdown   2.5.3    2020-12-01 [1] Github (rstudio/rmarkdown@beed481)
   servr       0.20     2020-10-19 [1] CRAN (R 4.0.2)                    
   stringi     1.5.3    2020-09-09 [1] CRAN (R 4.0.2)                    
   stringr     1.4.0    2019-02-10 [1] CRAN (R 4.0.0)                    
   tinytex     0.27     2020-11-01 [1] CRAN (R 4.0.2)                    
   xfun        0.19     2020-10-30 [1] CRAN (R 4.0.2)                    
   yaml        2.2.1    2020-02-01 [1] CRAN (R 4.0.0)      
  </code></pre>