Docs: G52 Circular Link

[satiowadahc]

https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g52

More information on G52 is in the [Local and Global Offsets](https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g52) section.

[andypugh]

Unfortunately the buildbot hasn't built docs for quite some time, so I don't know how long it will take for the change to make it to the online docs.
http://buildbot.linuxcnc.org/doc/

[satiowadahc]

Thanks for addressing it. Wasn't super worried, just pointing it out.

[rmu75]

maybe related 64b3203