gru op doc does not display correctly on paddle.org

[kexinzhao]

Paddle/paddle/operators/gru_op.cc

Lines 135 to 140 in 3557235

	\f[
	update \ gate: u_t = actGate(xu_t + W_u * h_{t-1} + b_u) \\
	reset \ gate: r_t = actGate(xr_t + W_r * h_{t-1} + b_r) \\
	output \ candidate: {h}_t = actNode(xc_t + W_c * dot(r_t, h_{t-1}) + b_c) \\
	output: h_t = dot((1 - u_t), h_{t-1}) + dot(u_t, {h}_t)
	\f]

I think the \f[ and \f] should be replaced by $$, respectively.

Currently, equation is not correctly shown here:
http://www.paddlepaddle.org/docs/develop/documentation/en/operators.html#permalink-15-gru

[guoshengCS]

Thanks. I will fix it.