fix: misuse of m flag

`m` flag means match newline with `^` and `$`, but what we want is to
match real start and end of string.
The correct "dot-all" flag is `s` which is used correctly.

Fixes #6

src/index.ts

@@ -28,7 +28,7 @@ function main() {
         }
       }
       if (event.text.length <= 2) return
-      if (!event.text.match(/^(\$+)([^$]+)\1$/m)) return
+      if (!event.text.match(/^(\$+)([^$]+)\1$/)) return
       const block = await logseq.Editor.getCurrentBlock()
       if (block === null) return
       openPopup(block.uuid, {

src/popup.ts

@@ -26,7 +26,7 @@ export async function openPopup(
   let delim = logseq.settings?.preferDisplay ? '$$' : '$'
   let newline = logseq.settings?.preferMultiline ? '\n' : ''
   if (originalContent) {
-    const match = originalContent.match(/^(?<delim>\$+)(?<newline>\n*)(?<content>.*)\2\1$/ms)
+    const match = originalContent.match(/^(?<delim>\$+)(?<newline>\n*)(?<content>.*)\2\1$/s)
     if (match !== null && match.groups !== undefined) {
       originalValue = match.groups.content
       delim = match.groups.delim