Put $ or $$ around math in csljson output.

Closes #9616.

src/Text/Pandoc/Writers/CslJson.hs

@@ -71,7 +71,8 @@ fromInline (Code _ t) = CslText t
 fromInline Space = CslText " "
 fromInline SoftBreak = CslText " "
 fromInline LineBreak = CslText "\n"
-fromInline (Math _ t) = CslText t
+fromInline (Math InlineMath t) = CslText $ "$" <> t <> "$"
+fromInline (Math DisplayMath t) = CslText $ "$$" <> t <> "$$"
 fromInline (RawInline _ _) = CslEmpty
 fromInline (Link _ ils _) = fromInlines ils
 fromInline (Image _ ils _) = fromInlines ils

test/command/9616.md

@@ -0,0 +1,16 @@
+```
+% pandoc -f bibtex -t csljson -s
+@MISC {3252037,
+    TITLE = {Isomorphism between projective varieties $\mathbf{P}^{1}$ and a conic in $\mathbf{P}^{2}$},
+    URL = {https://math.stackexchange.com/q/3252037}
+}
+^D
+[
+  {
+    "URL": "https://math.stackexchange.com/q/3252037",
+    "id": "3252037",
+    "title": "Isomorphism between projective varieties $\\mathbf{P}^{1}$ and a conic in $\\mathbf{P}^{2}$",
+    "type": ""
+  }
+]
+```