DATAMATRIX: add manual FNC1 support

CODE128: error on unrecognized extra escape sequences instead of
  just passing them thru;
  fix possible shifting before manual FNC1 in 2nd position
  after single alpha (otherwise won't be recognized as AIM)
  fix not removing manual FNC1 in 1st/2nd position from content
  segs (as implied by symbology identifier)
CLI: warn if both "--dmre" and "--square" given (as "--square"
  overwrites "--dmre")
common: new routines `z_isalpha()`, `z_extra_escapes()` and
  `z_ct_set_seg_extra_escapes_eci()`
library: new helper `supports_extra_escape_mode()`;
  fix some error_number dups
BWIPP: update to latest, and allow for removal of DBAR_LTD_CC RHS
  quiet zones & extra row when have add-on in EAN/UPC composites
test suite: fix BWIPP escaping
manual/man/tcl: update for DATAMATRIX manual FNC1 support
Windows: resource scripts: make more consistent (libzint, CLI, GUI)
win32/README: update with MSVC 2026

frontend_qt/grpC128.ui

@@ -48,12 +48,13 @@
       <item row="1" column="0" colspan="2">
        <widget class="QRadioButton" name="radC128ExtraEsc">
         <property name="text">
-         <string>&amp;Manual Code Sets and FNC1s (Extra Escape Mode)</string>
+         <string>&amp;Manual Code Sets and FNC1s (Extra Escape)</string>
         </property>
         <property name="toolTip">
          <string>Process special escape sequences &quot;\^A&quot;, &quot;\^B&quot;, &quot;\^C&quot; and
 &quot;\^@&quot; allowing manual Code Set selection and special
-escape sequence &quot;\^1&quot; allowing manual FNC1s</string>
+escape sequence &quot;\^1&quot; allowing manual FNC1s
+(literal &quot;\^&quot; may be escaped with &quot;\^^&quot;)</string>
         </property>
        </widget>
       </item>