present: document shebang and txtar for .play

[oxzi]

The "play" command for present does not only support Go code, which was
implicitly documented, but also generic scripts identified by a shebang
or txtar-encoded input - enabling Go modules.

The locally used implementation for "play" resides in
./playground/socket/socket.go. Mostly undocumented, this code first
checks the input for a shebang and, if present, executes input with the
shebang interpreter. This code also allows txtar-encoded input, which
can be used to "play" Go modules, including external dependencies.

Documenting the actual behavior helps users to understand and use the
software better. Personally, I initially wanted to patch Go module
support in present, just to find out everything is already there - just
undocumented.

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[gopherbot]

Message from Gopher Robot:

Patch Set 1:

(1 comment)

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