In Verilog and VHDL, <= is a symbol of assignment. For example:
always @ (posedge clk or negedge xrstn)
begin
if(!xrstn)
begin
sum_d <= 0;
end
else
begin
sum_d <= sum;
end
end
However, in Fira Code, the assignment symbol <= is rendered as a "less than or equal to" sign.

I hope there could be a stylistic option of rendering it.