Remove unintentional backslash from README.md (#8151)

Addresses review feedback from PR #8141 to remove a stray backslash
character at the end of line 9 in README.md.

The backslash (`\`) was a formatting artifact with no semantic purpose
that could cause rendering issues in some markdown parsers.

**Change:**
- Line 9: `README.md.\` → `README.md.`

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README.md

@@ -6,7 +6,7 @@ The Microsoft Authentication Library for JavaScript enables both client-side and
 
 ### Core, wrapper and extensions libraries
 
-The [`lib`](https://github.com/AzureAD/microsoft-authentication-library-for-js/tree/dev/lib) folder contains the source code for our libraries in active development. You will also find all the details about **installing the libraries** in their respective README.md.\
+The [`lib`](https://github.com/AzureAD/microsoft-authentication-library-for-js/tree/dev/lib) folder contains the source code for our libraries in active development. You will also find all the details about **installing the libraries** in their respective README.md.
 
 -   [Microsoft Authentication Library for JavaScript](lib/msal-browser/): A browser-based, framework-agnostic browser library that enables authentication and token acquisition with the Microsoft Identity platform in JavaScript applications. Implements the OAuth 2.0 [Authorization Code Flow with PKCE](https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-auth-code-flow), and is [OpenID-compliant](https://docs.microsoft.com/azure/active-directory/develop/v2-protocols-oidc).