Remove common token replacement

Under [Required Parameters](https://docs.microsoft.com/en-us/cli/azure/reference-index?view=azure-cli-latest#az_rest-required-parameters)

> Common token {subscriptionId} will be replaced with the current subscription ID specified by az account set

is inaccurate. Running `az rest --method get --url https://management.azure.com/subscriptions/{subscriptionId}/resources?api-version=2019-07-01 --url-parameters \$top=3` results in the error `az rest: 'utputformat' is not a valid value for '--output'.`

This error was mentioned in Azure/azure-cli#8778 meaning the curly braces causes the error. It should be removed to alleviate confusion and that the reader must replace {subscriptionId} with their subscription id.

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* ID: eeedb9a7-2aed-6727-4cfb-1515809d676e
* Version Independent ID: 2c83180d-22ad-db42-e2eb-f27f11977963
* Content: [az](https://docs.microsoft.com/en-us/cli/azure/reference-index?view=azure-cli-latest)
* Content Source: [latest/docs-ref-autogen/reference-index.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/master/latest/docs-ref-autogen/reference-index.yml)
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**