x/website: wrong package synopses on stdlib packages containing programs

[zephyrtronium]

https://golang.org/pkg/ currently shows the wrong package synopses on stdlib packages containing ignore-constrained programs intended for go run. E.g., the synopsis on package runtime is mkduff generates duff_*.s., on package os/exec is This is a test program that verifies that it can read from descriptor 3 and that no other descriptors are open., &c.

[zephyrtronium]

Probably related, the same page now shows pages for src/cmd, which I believe it did not do previously.

[prattmic]

cc @rsc

Perhaps http://golang.org/cl/296378 or one of the other CLs in the stack?

The March 10 snapshot of this page at https://web.archive.org/web/*/https://golang.org/pkg/ has the correct descriptions, so it seems recent.

[kortschak]

In all the cases that this is happening, the package documentation synopsis is obtained from a file that has a // +build tag (from memory all are ignore, though that's not likely relevant).

[gopherbot]

Change https://golang.org/cl/311089 mentions this issue: internal/pkgdoc: fix synopsis pkg name == dir name matching

[zephyrtronium]

https://golang.org/pkg/ is still showing packages under src/cmd. This issue is not entirely resolved.