style(latex): replace $$ with recommended \[ \] for Centered Math snippet

[asaberui1]

Description

This PR updates the Centered Math snippet to use \[ ... \] instead of $$...$$.

Motivation

In modern LaTeX, using \[ ... \] is widely considered a best practice over the plain TeX syntax $$...$$ for unnumbered displayed equations. The benefits include:

1. Better Spacing: \[ ... \] handles vertical spacing more consistently.
2. Error Handling: It provides better error checking and prevents common alignment issues.
3. Compatibility: It integrates more seamlessly with document classes and packages like amsmath.

Reference: StackExchange: Why is [ ... ] preferable to $$...$$?

Changes

Modified the Centered Math snippet body:

• From: "body": ["\\$$ $0 \\$$"]
• To:

  "body": [
      "\\[",
      "\t$0",
      "\\]"
  ]