update x5t description

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cc: @nickludwig

Author: nickludwig

articles/active-directory/develop/active-directory-certificate-credentials.md

@@ -34,7 +34,7 @@ To compute the assertion, you can use one of the many JWT libraries in the langu
 | --- | --- |
 | `alg` | Should be **RS256** |
 | `typ` | Should be **JWT** |
-| `x5t` | The X.509 certificate hash's (also known as the cert's SHA-1 *thumbprint*) Hex representation encoded as a Base64url string value. For example, given an X.509 certificate hash of `84E05C1D98BCE3A5421D225B140B36E86A3D5534` (Hex), the `x5t` claim would be `hOBcHZi846VCHSJbFAs26Go9VTQ=` (Base64url). |
+| `x5t` | Base64url-encoded SHA-1 thumbprint of the X.509 certificate thumbprint. For example, given an X.509 certificate hash of `84E05C1D98BCE3A5421D225B140B36E86A3D5534` (Hex), the `x5t` claim would be `hOBcHZi846VCHSJbFAs26Go9VTQ=` (Base64url). |
 
 ### Claims (payload)