#2464 Tag borderwidth is leaking horizontally

[Kaitzschu]

Observed behavior: when setting -relief non-flat and -borderwidth greater than tag width then relief border extends from left and right side over the area of tagged characters.

Desired behavior: border being clipped horizontally the same way as it is clipped vertically, not extending the tagged area.

Code example:

font configure TkFixedFont -size 20
pack [text .t -font TkFixedFont -height 5 -width 5]
.t tag configure relief -relief solid -borderwidth 100
.t insert 1.0 {
ooo
o} {} x relief {o
ooo
}