完善 schema 模块的静态方法使用说明

[liuweiGL]

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resolve #1307

[codecov-commenter]

Codecov Report

Merging #1310 (381e25b) into formily_next (388288a) will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff              @@
##           formily_next    #1310   +/-   ##
=============================================
  Coverage         89.96%   89.96%           
=============================================
  Files               136      136           
  Lines              5927     5927           
  Branches           1505     1505           
=============================================
  Hits               5332     5332           
  Misses              592      592           
  Partials              3        3           

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