adding language var back

Author: dfirebaugh

services/gitdiff/gitdiff.go

@@ -301,6 +301,10 @@ func (diffSection *DiffSection) GetComputedInlineDiffFor(diffLine *DiffLine, loc
 		diff2           string
 	)
 
+	language := ""
+	if diffSection.file != nil {
+		language = diffSection.file.Language
+	}
 	// try to find equivalent diff line. ignore, otherwise
 	switch diffLine.Type {
 	case DiffLineSection:
@@ -331,7 +335,7 @@ func (diffSection *DiffSection) GetComputedInlineDiffFor(diffLine *DiffLine, loc
 	}
 
 	hcd := newHighlightCodeDiff()
-	diffRecord := hcd.diffWithHighlight(diffSection.FileName, diffSection.file.Language, diff1, diff2)
+	diffRecord := hcd.diffWithHighlight(diffSection.FileName, language, diff1, diff2)
 	// it seems that Gitea doesn't need the line wrapper of Chroma, so do not add them back
 	// if the line wrappers are still needed in the future, it can be added back by "diffToHTML(hcd.lineWrapperTags. ...)"
 	diffHTML := html.UnescapeString(diffToHTML(nil, diffRecord, diffLine.Type))