accounts: documentation fixes (ethereum#22645)

* replaces `an chance` with `a chance`
* replaces `SignHashWithPassphrase` with `SignTextWithPassphrase` as there was no SignHashWithPasspharse function in the file

accounts/accounts.go

@@ -113,7 +113,7 @@ type Wallet interface {
 	SignData(account Account, mimeType string, data []byte) ([]byte, error)
 
 	// SignDataWithPassphrase is identical to SignData, but also takes a password
-	// NOTE: there's an chance that an erroneous call might mistake the two strings, and
+	// NOTE: there's a chance that an erroneous call might mistake the two strings, and
 	// supply password in the mimetype field, or vice versa. Thus, an implementation
 	// should never echo the mimetype or return the mimetype in the error-response
 	SignDataWithPassphrase(account Account, passphrase, mimeType string, data []byte) ([]byte, error)
@@ -127,7 +127,7 @@ type Wallet interface {
 	// a password to decrypt the account, or a PIN code o verify the transaction),
 	// an AuthNeededError instance will be returned, containing infos for the user
 	// about which fields or actions are needed. The user may retry by providing
-	// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock
+	// the needed details via SignTextWithPassphrase, or by other means (e.g. unlock
 	// the account in a keystore).
 	//
 	// This method should return the signature in 'canonical' format, with v 0 or 1