redundant `encode_signed_varint` function

[arhik]

After #42 merge encode_signed_varint! doesn't match its functionality and lost its purpose. So this function can be removed altogether.

cuTile.jl/src/bytecode/writer.jl

Lines 293 to 302 in 2c52a53

	"""
	encode_signed_varint!(buf, value)
	Encode a signed integer as a variable-length integer.
	Uses zigzag encoding for signed values.
	"""
	function encode_signed_varint!(buf::Vector{UInt8}, value::Union{UInt16, UInt32, UInt64})
	# For float bits, encode as unsigned varint
	encode_varint!(buf, UInt64(value))
	end