gitk: use $config_variables as list for save/restore

gitk includes many user defined configuration variables, has all of
these are listed in $config_variables. But this list is not used to
define the variables to be loaded, saved, or restored when cancelling
the configuration dialog, and developers must maintain separate lists of
variables for these purposes. This leads to unnecessary errors and merge
conflicts. Let's replace those separate lists with $config_variables to
make maintenance easier.

While we are on topic, sort the list of names in $config_variables.
This makes it simpler to scan and has fewer chances of conflicts
when new names are introduced.

Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Mark Levedahl <mlevedahl@gmail.com>

gitk

@@ -11669,10 +11669,8 @@ proc create_prefs_page {w} {
 }
 
 proc prefspage_general {notebook} {
-    global NS maxwidth maxgraphpct showneartags showlocalchanges
-    global tabstop wrapcomment wrapdefault limitdiffs
-    global autocopy autoselect autosellen extdifftool perfile_attrs
-    global hideremotes want_ttk have_ttk maxrefs web_browser
+    global NS have_ttk
+    global {*}$::config_variables
 
     set page [create_prefs_page $notebook.general]
 
@@ -11833,11 +11831,8 @@ proc prefspage_fonts {notebook} {
 }
 
 proc doprefs {} {
-    global maxwidth maxgraphpct use_ttk NS
-    global oldprefs prefstop showneartags showlocalchanges
-    global uicolor bgcolor fgcolor ctext diffcolors selectbgcolor markbgcolor
-    global tabstop limitdiffs autoselect autosellen extdifftool perfile_attrs
-    global hideremotes want_ttk have_ttk wrapcomment wrapdefault
+    global use_ttk NS oldprefs prefstop
+    global {*}$::config_variables
 
     set top .gitkprefs
     set prefstop $top
@@ -11845,8 +11840,7 @@ proc doprefs {} {
         raise $top
         return
     }
-    foreach v {maxwidth maxgraphpct showneartags showlocalchanges \
-                   limitdiffs tabstop perfile_attrs hideremotes want_ttk wrapcomment wrapdefault} {
+    foreach v $::config_variables {
         set oldprefs($v) [set $v]
     }
     ttk_toplevel $top
@@ -11970,10 +11964,9 @@ proc setfg {c} {
 
 proc prefscan {} {
     global oldprefs prefstop
+    global {*}$::config_variables
 
-    foreach v {maxwidth maxgraphpct showneartags showlocalchanges \
-                   limitdiffs tabstop perfile_attrs hideremotes want_ttk wrapcomment wrapdefault} {
-        global $v
+    foreach v $::config_variables {
         set $v $oldprefs($v)
     }
     catch {destroy $prefstop}
@@ -11982,11 +11975,8 @@ proc prefscan {} {
 }
 
 proc prefsok {} {
-    global maxwidth maxgraphpct
-    global oldprefs prefstop showneartags showlocalchanges
-    global fontpref mainfont textfont uifont
-    global limitdiffs treediffs perfile_attrs
-    global hideremotes wrapcomment wrapdefault
+    global oldprefs prefstop fontpref treediffs
+    global {*}$::config_variables
     global ctext
 
     catch {destroy $prefstop}
@@ -12609,19 +12599,65 @@ catch {
 config_check_tmp_exists 50
 
 set config_variables {
-    mainfont textfont uifont tabstop findmergefiles maxgraphpct maxwidth
-    cmitmode wrapcomment wrapdefault autocopy autoselect autosellen
-    showneartags maxrefs visiblerefs
-    hideremotes showlocalchanges datetimeformat limitdiffs uicolor want_ttk
-    bgcolor fgcolor uifgcolor uifgdisabledcolor colors diffcolors mergecolors
-    markbgcolor diffcontext selectbgcolor foundbgcolor currentsearchhitbgcolor
-    extdifftool perfile_attrs headbgcolor headfgcolor headoutlinecolor
-    remotebgcolor tagbgcolor tagfgcolor tagoutlinecolor reflinecolor
-    filesepbgcolor filesepfgcolor linehoverbgcolor linehoverfgcolor
-    linehoveroutlinecolor mainheadcirclecolor workingfilescirclecolor
-    indexcirclecolor circlecolors linkfgcolor circleoutlinecolor diffbgcolors
+    autocopy
+    autoselect
+    autosellen
+    bgcolor
+    circlecolors
+    circleoutlinecolor
+    cmitmode
+    colors
+    currentsearchhitbgcolor
+    datetimeformat
+    diffbgcolors
+    diffcolors
+    diffcontext
+    extdifftool
+    fgcolor
+    filesepbgcolor
+    filesepfgcolor
+    findmergefiles
+    foundbgcolor
+    headbgcolor
+    headfgcolor
+    headoutlinecolor
+    hideremotes
+    indexcirclecolor
+    limitdiffs
+    linehoverbgcolor
+    linehoverfgcolor
+    linehoveroutlinecolor
+    linkfgcolor
+    mainfont
+    mainheadcirclecolor
+    markbgcolor
+    maxgraphpct
+    maxrefs
+    maxwidth
+    mergecolors
+    perfile_attrs
+    reflinecolor
+    remotebgcolor
+    selectbgcolor
+    showlocalchanges
+    showneartags
+    tabstop
+    tagbgcolor
+    tagfgcolor
+    tagoutlinecolor
+    textfont
+    uicolor
+    uifgcolor
+    uifgdisabledcolor
+    uifont
+    visiblerefs
+    want_ttk
     web_browser
+    workingfilescirclecolor
+    wrapcomment
+    wrapdefault
 }
+
 foreach var $config_variables {
     config_init_trace $var
     trace add variable $var write config_variable_change_cb