docs: Add key-pair authentication for Snowflake credentials (#4110)

Co-authored-by: Kartik Balasubramanian <22399046+HumanistSerif@users.noreply.github.com>

docs/integrations/builtin/credentials/snowflake.md

@@ -16,23 +16,41 @@ Create a [Snowflake](https://www.snowflake.com/en/) account.
 
 ## Supported authentication methods
 
-- Database connection
+- [Password](#using-password-authentication)
+- [Key-pair](#using-key-pair-authentication)
 
 ## Related resources
 
 Refer to [Snowflake's API documentation](https://docs.snowflake.com/en/api-reference) and [SQL Command Reference](https://docs.snowflake.com/en/sql-reference-commands) for more information about the service.
 
-## Using database connection
+## Common configuration fields
 
-To configure this credential, you'll need:
+Both authentication methods require the following fields:
 
 - An **Account** name: Your account name is the string of characters located between `https://` and `snowflakecomputing.com` in your Snowflake URL. For example, if the URL of your Snowflake account is `https://abc.eu-central-1.snowflakecomputing.com` then the name of your account is `abc.eu-central-1`.
 - A **Database**: Enter the name of the [database](https://docs.snowflake.com/en/sql-reference/sql/use-database) the credential should connect to.
 - A **Warehouse**: Enter the name of the default virtual [warehouse](https://docs.snowflake.com/en/sql-reference/sql/use-warehouse) to use for the session after connecting. n8n uses this warehouse for performing queries, loading data, and so on.
-- A **Username**
-- A **Password**
 - A **Schema**: Enter the [schema](https://docs.snowflake.com/en/sql-reference/sql/use-schema) you want to use after connecting.
 - A **Role**: Enter the security [role](https://docs.snowflake.com/en/sql-reference/sql/use-role) you want to use after connecting.
 - **Client Session Keep Alive**: By default, client connections typically time out three or four hours after the most recent query execution. Turning this setting on sets the `clientSessionKeepAlive` parameter to true: the server will keep the client's connection alive indefinitely, even if the connection doesn't execute any queries.
 
 Refer to [Session Commands](https://docs.snowflake.com/en/sql-reference/commands-session) for more information on these settings.
+
+## Using password authentication
+
+In addition to the [common configuration fields](#common-configuration-fields), password authentication requires:
+
+- A **Username**
+- A **Password**
+
+## Using key-pair authentication
+
+Key-pair authentication provides enhanced security as an alternative to password-based authentication. This method uses a public-private key pair for authentication.
+
+In addition to the [common configuration fields](#common-configuration-fields), key-pair authentication requires:
+
+- A **Username**: The Snowflake user that has the public key assigned to it.
+- A **Private Key**: The private key in PEM format (PKCS#8). This should be the full content of your private key file, including the `-----BEGIN ENCRYPTED PRIVATE KEY-----` and `-----END ENCRYPTED PRIVATE KEY-----` delimiters (or `-----BEGIN PRIVATE KEY-----` and `-----END PRIVATE KEY-----` for unencrypted keys).
+- A **Passphrase** (optional): If your private key is encrypted, enter the passphrase used to encrypt it. Leave this field empty if you're using an unencrypted private key.
+
+Refer to [Snowflake's key-pair authentication documentation](https://docs.snowflake.com/en/user-guide/key-pair-auth) for more information about generating and configuring key pairs.