Move .tcl build scripts to infosrc

This is where all the other build scripts live.

And it's where the input to these files lives.

diff --git a/doc/info/arrowgen.tcl b/doc/infosrc/arrowgen.tcl
similarity index 100%
rename from doc/info/arrowgen.tcl
rename to doc/infosrc/arrowgen.tcl

diff --git a/doc/info/shapegen.tcl b/doc/infosrc/shapegen.tcl
similarity index 100%
rename from doc/info/shapegen.tcl
rename to doc/infosrc/shapegen.tcl