add blocks API docs

[Roger-luo]

pkg> dev lib/YaoBlocks lib/YaoAPI lib/YaoArrayRegister lib/YaoSym .
julia> using LiveServer; servedocs(;skip_dirs=["docs/src/assets", "docs/src/generated"])

[codecov[bot]]

Codecov Report

Merging #371 (a0f3b24) into master (dc9c7d2) will decrease coverage by 0.92%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #371      +/-   ##
==========================================
- Coverage   87.15%   86.22%   -0.93%     
==========================================
  Files          73       26      -47     
  Lines        3799     1387    -2412     
==========================================
- Hits         3311     1196    -2115     
+ Misses        488      191     -297     

Impacted Files	Coverage Δ
lib/YaoArrayRegister/src/register.jl	96.92% <0.00%> (ø)
lib/YaoBlocks/src/composite/chain.jl
lib/YaoBlocks/src/composite/control.jl
lib/YaoBlocks/src/composite/kron.jl
lib/YaoBlocks/src/composite/put_block.jl
lib/YaoBlocks/src/composite/reduce.jl
lib/YaoBlocks/src/composite/unitary_channel.jl
lib/YaoBlocks/src/primitive/const_gate_tools.jl
lib/YaoBlocks/src/primitive/general_matrix_gate.jl
lib/YaoBlocks/src/primitive/identity_gate.jl
... and 38 more

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