miscellaneous improvements to generated docs

* introduce std.json.WriteStream API for writing json
   data to a stream
 * add WIP tools/merge_anal_dumps.zig for merging multiple semantic
   analysis dumps into one. See #3028
 * add std.json.Array, improves generated docs
 * add test for `std.process.argsAlloc`, improves test coverage and
   generated docs
01b2c291d5Andrew Kelley committed on 10/11/2019, 3:25:40 AMparent7b20205
5 files changedLine totals unavailable