sconstruct: correctly detect the language of xliff files when trying …

…to skip English (#17143)

Summary of the issue:
The NVDA build system creates html from markdown files. For any language other than English, these markdown files should be themselves generated from xliff files.
However, a rather strange and incorrect line of code caused this to also happen for English, as the line was not correctly detecting the language.

Description of user facing changes
English user documentation in alpha builds should be based on the very latest markdown files, rather than the last beta from the previous release.

sconstruct

@@ -335,7 +335,7 @@ numberedHeadingsStyle = os.path.join(userDocsDir.path, "numberedHeadings.css")
 
 # Create Non-english md files in user_docs from localized xliff and English skel files
 for xliffFile in env.Glob(os.path.join(userDocsDir.path, "*", "*.xliff")):
-	lang = os.path.basename(xliffFile.path).split(".")[0]
+	lang = os.path.split(os.path.dirname(xliffFile.path))[-1]
 	if lang == "en":
 		continue
 	mdFile = os.path.splitext(xliffFile.path)[0] + ".md"