Revert "Respect org-src-lang modes"

This reverts commit 2319914d63.

Reverting this for the time being as it's failing the tests.

/cc @ahendriksen

ox-blackfriday.el

@@ -885,7 +885,6 @@ This function is adapted from `org-html-special-block'."
 
 INFO is a plist used as a communication channel."
   (let* ((lang (org-element-property :language src-block))
-         (lang (or (cdr (assoc lang org-src-lang-modes)) lang))
          (code (org-export-format-code-default src-block info))
          (parent-element (org-export-get-parent src-block))
          (parent-type (car parent-element))

ox-hugo.el

@@ -2587,7 +2587,6 @@ Hugo \"highlight\" shortcode features:
 CONTENTS is nil.  INFO is a plist used as a communication
 channel."
   (let* ((lang (org-element-property :language src-block))
-         (lang (or (cdr (assoc lang org-src-lang-modes)) lang))
          (parameters-str (org-element-property :parameters src-block))
          (parameters (org-babel-parse-header-arguments parameters-str))
          (is-fm-extra (cdr (assoc :front_matter_extra parameters)))