fix: katex regexp

Signed-off-by: Innei <i@innei.in>

Author: Innei

src/app/feed/route.tsx

@@ -164,7 +164,7 @@ const ALERT_BLOCKQUOTE_R =
 
 const KateXRule: MarkdownToJSX.Rule = {
   match: simpleInlineRegex(
-    /^\$\s{0,}((?:\[.*?\]|<.*?>(?:.*?<.*?>)?|`.*?`|.)*?)\s{0,}\$/,
+    /^(?!\\)\$\s{0,}((?:\[(?:[^$]|(?=\\)\$)*?\]|<(?:[^$]|(?=\\)\$)*?>(?:(?:[^$]|(?=\\)\$)*?<(?:[^$]|(?=\\)\$)*?>)?|`(?:[^$]|(?=\\)\$)*?`|(?:[^$]|(?=\\)\$))*?)\s{0,}(?!\\)\$/,
   ),
   order: Priority.LOW,
   parse: parseCaptureInline,

src/components/ui/markdown/parsers/katex.tsx

@@ -10,7 +10,7 @@ const useInsertionEffect = React.useInsertionEffect || React.useEffect
 //  $ c = \pm\sqrt{a^2 + b^2} $
 export const KateXRule: MarkdownToJSX.Rule = {
   match: simpleInlineRegex(
-    /^\$\s{0,}((?:\[.*?\]|<.*?>(?:.*?<.*?>)?|`.*?`|.)*?)\s{0,}\$/,
+    /^(?!\\)\$\s{0,}((?:\[(?:[^$]|(?=\\)\$)*?\]|<(?:[^$]|(?=\\)\$)*?>(?:(?:[^$]|(?=\\)\$)*?<(?:[^$]|(?=\\)\$)*?>)?|`(?:[^$]|(?=\\)\$)*?`|(?:[^$]|(?=\\)\$))*?)\s{0,}(?!\\)\$/,
   ),
   order: Priority.MED,
   parse(capture) {