gitk: Improve display of list of nearby tags and heads

This provides a control in the preferences pane for the limit on
how many tags or heads are displayed with the commit details under
the Branch(es), Precedes and Follows headings.  This limit is now
saved in ~/.gitk so that changes are persistent.

This also applies word-wrapping to the list of tags or heads under
the Branch, Precedes and Follows headings, so that long lists are
more readable.

Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -2375,6 +2375,7 @@ proc makewindow {} {
     $ctext tag conf msep -font textfontbold
     $ctext tag conf found -back yellow
     $ctext tag conf currentsearchhit -back orange
+    $ctext tag conf wwrap -wrap word
 
     .pwbottom add .bleft
     if {!$use_ttk} {
@@ -2721,7 +2722,7 @@ proc savestuff {w} {
     global cmitmode wrapcomment datetimeformat limitdiffs
     global colors uicolor bgcolor fgcolor diffcolors diffcontext selectbgcolor
     global autoselect autosellen extdifftool perfile_attrs markbgcolor use_ttk
-    global hideremotes want_ttk
+    global hideremotes want_ttk maxrefs
 
     if {$stuffsaved} return
     if {![winfo viewable .]} return
@@ -2743,6 +2744,7 @@ proc savestuff {w} {
 	puts $f [list set autoselect $autoselect]
 	puts $f [list set autosellen $autosellen]
 	puts $f [list set showneartags $showneartags]
+	puts $f [list set maxrefs $maxrefs]
 	puts $f [list set hideremotes $hideremotes]
 	puts $f [list set showlocalchanges $showlocalchanges]
 	puts $f [list set datetimeformat $datetimeformat]
@@ -6906,6 +6908,7 @@ proc appendrefs {pos ids var} {
 	    set sep ", "
 	}
     }
+    $ctext tag add wwrap "$pos linestart" "$pos lineend"
     $ctext conf -state disabled
     return [llength $tags]
 }
@@ -10937,7 +10940,7 @@ proc create_prefs_page {w} {
 proc prefspage_general {notebook} {
     global NS maxwidth maxgraphpct showneartags showlocalchanges
     global tabstop limitdiffs autoselect autosellen extdifftool perfile_attrs
-    global hideremotes want_ttk have_ttk
+    global hideremotes want_ttk have_ttk maxrefs
 
     set page [create_prefs_page $notebook.general]
 
@@ -10966,9 +10969,12 @@ proc prefspage_general {notebook} {
     ${NS}::label $page.tabstopl -text [mc "Tab spacing"]
     spinbox $page.tabstop -from 1 -to 20 -width 4 -textvariable tabstop
     grid x $page.tabstopl $page.tabstop -sticky w
-    ${NS}::checkbutton $page.ntag -text [mc "Display nearby tags"] \
+    ${NS}::checkbutton $page.ntag -text [mc "Display nearby tags/heads"] \
 	-variable showneartags
     grid x $page.ntag -sticky w
+    ${NS}::label $page.maxrefsl -text [mc "Maximum # tags/heads to show"]
+    spinbox $page.maxrefs -from 1 -to 1000 -width 4 -textvariable maxrefs
+    grid x $page.maxrefsl $page.maxrefs -sticky w
     ${NS}::checkbutton $page.ldiff -text [mc "Limit diffs to listed paths"] \
 	-variable limitdiffs
     grid x $page.ldiff -sticky w