Enable SA1517 and fix noncompliance (except in Cores)

"Code should not contain blank lines at start of file"

.global.editorconfig.ini

@@ -562,7 +562,7 @@ dotnet_diagnostic.SA1515.severity = silent
 # Elements should be separated by blank line
 dotnet_diagnostic.SA1516.severity = silent
 # Code should not contain blank lines at start of file
-dotnet_diagnostic.SA1517.severity = silent
+dotnet_diagnostic.SA1517.severity = warning
 # Use line endings correctly at end of file
 dotnet_diagnostic.SA1518.severity = silent
 # Braces should not be omitted from multi-line child statement

src/BizHawk.Emulation.Common/Database/FirmwarePatchOption.cs

@@ -1,4 +1,3 @@
-
 using System.Collections.Generic;
 
 namespace BizHawk.Emulation.Common

src/BizHawk.Emulation.Cores/BizHawk.Emulation.Cores.csproj

@@ -5,7 +5,7 @@
 	<Import Project="../MainSlnCommon.props" />
 	<PropertyGroup>
 		<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-		<NoWarn>$(NoWarn);CA1806;CA1825;CA2214;MA0060;MA0084;MA0090;MA0140;SA1100;SA1120;SA1129;SA1137;SA1205;SA1208;SA1400;SA1514</NoWarn>
+		<NoWarn>$(NoWarn);CA1806;CA1825;CA2214;MA0060;MA0084;MA0090;MA0140;SA1100;SA1120;SA1129;SA1137;SA1205;SA1208;SA1400;SA1514;SA1517</NoWarn>
 		<Nullable>disable</Nullable>
 	</PropertyGroup>
 	<ItemGroup>

src/BizHawk.Emulation.DiscSystem/DiscMountPolicy.cs

@@ -1,4 +1,3 @@
-
 namespace BizHawk.Emulation.DiscSystem
 {
 	/// <summary>

src/BizHawk.Emulation.DiscSystem/Internal/Jobs/Synthesize_Leadout_Job.cs

@@ -1,9 +1,6 @@
-
-
-//TODO - generate correct Q subchannel CRC
-
 namespace BizHawk.Emulation.DiscSystem
 {
+	//TODO - generate correct Q subchannel CRC
 
 	/// <summary>
 	/// generates lead-out sectors according to very crude approximations