Documentation reference shard_count heuristics

[pauldraper]

The documentation for shard_count says:

This value will override any heuristics used to determine the number of parallel shards with which to run the test. Note that for some test rules, this parameter may be required to enable sharding in the first place. Also see --test_sharding_strategy.

But the docs also say the only permitted values for --test_sharding_strategy are explicit and disabled. In other words, Bazel never shards a test that doesn't specify shard_count.

The reference to heuristics appears to be vestigial (or future?).