Added icons for "Previous/Next Difference"

New StreamGeometry "Icons.Diff.Prev" / "Icons.Diff.Next" using SVG paths from "arrow_up_regular" / "arrow_down_regular" at https://avaloniaui.github.io/icons.html.

Author: goran-w

src/Resources/Icons.axaml

@@ -25,6 +25,8 @@
   <StreamGeometry x:Key="Icons.Detached">M128 183C128 154 154 128 183 128h521c30 0 55 26 55 55v38c0 17-17 34-34 34s-34-17-34-34v-26H196v495h26c17 0 34 17 34 34s-17 34-34 34h-38c-30 0-55-26-55-55V183zM380 896h-34c-26 0-47-21-47-47v-90h68V828h64V896H380c4 0 0 0 0 0zM759 828V896h90c26 0 47-21 47-47v-90h-68V828h-68zM828 435H896V346c0-26-21-47-47-47h-90v68H828v68zM435 299v68H367V439H299V346C299 320 320 299 346 299h90zM367 649H299v-107h68v107zM546 367V299h107v68h-107zM828 546H896v107h-68v-107zM649 828V896h-107v-68h107zM730 508v188c0 17-17 34-34 34h-188c-17 0-34-17-34-34s17-34 34-34h102l-124-124c-13-13-13-34 0-47 13-13 34-13 47 0l124 124V512c0-17 17-34 34-34 21-4 38 9 38 30z</StreamGeometry>
   <StreamGeometry x:Key="Icons.Detail">M889 0H135c-32 0-59 26-59 59v906c0 32 26 59 59 59h753c32 0 59-26 59-59v-906c1-33-26-59-58-59zm-165 177c31 0 56 25 56 56s-25 56-56 56-56-25-56-56 25-56 56-56zm-212 0c31 0 56 25 56 56S543 288 512 288s-56-25-56-56S481 177 512 177zm-212 0c31 0 56 25 56 56s-25 56-56 56-56-25-56-56 25-56 56-56zm209 606H285c-25 0-44-20-44-44 0-25 20-44 44-44h224c25 0 44 20 44 44 0 24-20 44-44 44zm230-212H285c-25 0-44-20-44-44 0-25 20-44 44-44h453c25 0 44 20 44 44 1 24-20 44-44 44z</StreamGeometry>
   <StreamGeometry x:Key="Icons.Diff">M854 307 611 73c-6-6-14-9-22-9H296c-4 0-8 4-8 8v56c0 4 4 8 8 8h277l219 211V824c0 4 4 8 8 8h56c4 0 8-4 8-8V330c0-9-4-17-10-23zM553 201c-6-6-14-9-23-9H192c-18 0-32 14-32 32v704c0 18 14 32 32 32h512c18 0 32-14 32-32V397c0-9-3-17-9-23L553 201zM568 753c0 4-3 7-8 7h-225c-4 0-8-3-8-7v-42c0-4 3-7 8-7h225c4 0 8 3 8 7v42zm0-220c0 4-3 7-8 7H476v85c0 4-3 7-7 7h-42c-4 0-7-3-7-7V540h-85c-4 0-8-3-8-7v-42c0-4 3-7 8-7H420v-85c0-4 3-7 7-7h42c4 0 7 3 7 7V484h85c4 0 8 3 8 7v42z</StreamGeometry>
+  <StreamGeometry x:Key="Icons.Diff.Prev">M4.21157,12.7326 C3.9244,13.0312 3.93361,13.5059 4.23213,13.7931 C4.53064,14.0803 5.00543,14.0711 5.29259,13.7725 L13.2521,5.49831 L13.2521,24.2511 C13.2521,24.6653 13.5879,25.0011 14.0021,25.0011 C14.4163,25.0011 14.7521,24.6653 14.7521,24.2511 L14.7521,5.4993 L22.7106,13.7725 C22.9978,14.0711 23.4726,14.0803 23.7711,13.7931 C24.0696,13.5059 24.0788,13.0312 23.7916,12.7326 L14.7223,3.30466 C14.3289,2.89568 13.6743,2.89568 13.2809,3.30466 L4.21157,12.7326 Z</StreamGeometry>
+  <StreamGeometry x:Key="Icons.Diff.Next">M23.7916,15.2664 C24.0788,14.9679 24.0696,14.4931 23.7711,14.206 C23.4726,13.9188 22.9978,13.928 22.7106,14.2265 L14.7511,22.5007 L14.7511,3.74792 C14.7511,3.33371 14.4153,2.99792 14.0011,2.99792 C13.5869,2.99792 13.2511,3.33371 13.2511,3.74793 L13.2511,22.4998 L5.29259,14.2265 C5.00543,13.928 4.53064,13.9188 4.23213,14.206 C3.93361,14.4931 3.9244,14.9679 4.21157,15.2664 L13.2809,24.6944 C13.6743,25.1034 14.3289,25.1034 14.7223,24.6944 L23.7916,15.2664 Z</StreamGeometry>
   <StreamGeometry x:Key="Icons.DoubleDown">M256 224l0 115L512 544l256-205 0-115-256 205L256 224zM512 685l-256-205L256 595 512 800 768 595l0-115L512 685z</StreamGeometry>
   <StreamGeometry x:Key="Icons.DoubleUp">M768 800V685L512 480 256 685V800l256-205L768 800zM512 339 768 544V429L512 224 256 429V544l256-205z</StreamGeometry>
   <StreamGeometry x:Key="Icons.Down">M509 546l271-271 91 91-348 349-1-1-13 13-363-361 91-91z</StreamGeometry>