Fix documentation for RootOfTrust.get_collateral

[tjade273]

The description of RootofTrust.get_collateral incorrectly claimed that a true value prevents fetching collateral when in fact this value gets passed directly into the Options.GetCollateral field which (correctly) claims the opposite

go-tdx-guest/verify/verify.go

Line 1505 in ffb0869

GetCollateral: rot.GetCollateral,

go-tdx-guest/verify/verify.go

Lines 183 to 184 in ffb0869

	// GetCollateral set to true if the verifier should retrieve the collaterals from the network using PCS.
	GetCollateral bool