xwininfo: add page; xkill: update page (#11945)

* xwininfo: add page ant pt_BR translation

* xkill: update page and pt_BR translation

* xwininfo: update pt_BR translation

* xwininfo: fix ID casing and ellipsis

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

* xwininfo: fix ID casing in pt_BR

---------

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Isaac Vicente <isaacvicentsocial@gmail.com>

pages/common/xwininfo.md

@@ -0,0 +1,25 @@
+# xwininfo
+
+> Display information about windows.
+> See also: `xprop`, `xkill`.
+> More information: <https://www.x.org/releases/current/doc/man/man1/xwininfo.1.xhtml>.
+
+- Display a cursor to select a window to display its attributes (id, name, size, position, ...):
+
+`xwininfo`
+
+- Display the tree of all windows:
+
+`xwininfo -tree -root`
+
+- Display the attributes of a window with a specific ID:
+
+`xwininfo -id {{id}}`
+
+- Display the attributes of a window with a specific name:
+
+`xwininfo -name {{name}}`
+
+- Display the ID of a window searching by name:
+
+`xwininfo -tree -root | grep {{keyword}} | head -1 | perl -ne 'print $1 if /(0x[\da-f]+)/ig;'`