BUG: wrong usage for package loading with multiple versions available

hi,
The "-exact" option does NOT include the PARTIAL version number. To use the
tcltest-2.3.8 package the EXACT version have to be "known".
The CORE problem is that tcltest-2.3 and tcltest-2-5 have partly DIFFERENT
syntax. The command "package require tcltest 2.3" should load the LATEST
patch level from "tcltest-2.3.X"
package require Tcl 8.5
 > 8.5.19
package versions tcltest
 > 2.3.8 2.5.3
info library
 > /path/to/lib/tcl8.5
catch {package require -exact tcltest 2.3} msg
 > 1
set msg
 > can't find package tcltest exactly 2.3
package require tcltest 2.3
 > 2.5.3
package require Tcl 8.5
 > 8.6.12
package versions tcltest
 > 2.3.8 2.5.3
info library
 > /path/to/lib/tcl8.6
catch {package require -exact tcltest 2.3} msg
 > 1
set msg
 > can't find package tcltest exactly 2.3
package require tcltest 2.3
 > 2.5.3