Fix typos and formatting issues in README.md

[Komali0706]

• Removed duplicate “### Having troubles?” heading.
• Fixed table / heading nesting under Firebase product integrations.

4. Minor style improvements:

• Improved readability of sentences.
• Ensured consistent capitalization and punctuation throughout README.

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Git Commands to Commit These Changes

# Stage the README
git add README.md

# Commit the changes
git commit -m "Fix typos and formatting issues in README.md"

# Push to your branch (if on a feature/fix branch)
git push -u origin fix-readme-typos

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