Support binary integer literals and digit separators

Example: 0b10000000'00000000'00000000'00000000

I rewrote the pattern to match integer literals so it’s stricter though will still match a partially typed number like ‘0x’ or one with a trailing digit separator (also considered partially typed), although here it marks the trailing separator as invalid.

Syntaxes/C.plist

@@ -80,8 +80,31 @@
 			<string>#sizeof</string>
 		</dict>
 		<dict>
+			<key>captures</key>
+			<dict>
+				<key>inc</key>
+				<dict>
+					<key>name</key>
+					<string>invalid.illegal.digit-separator-should-not-be-last.c++</string>
+				</dict>
+			</dict>
 			<key>match</key>
-			<string>\b((0(x|X)[0-9a-fA-F]*)|(([0-9]+\.?[0-9]*)|(\.[0-9]+))((e|E)(\+|-)?[0-9]+)?)(L|l|UL|ul|u|U|F|f|ll|LL|ull|ULL)?\b</string>
+			<string>(?x)\b
+			(  (?i:
+			      0x ( \h+    ( ' \h+    )* )?  # Hexadecimal
+			   |  0b ( [0-1]+ ( ' [0-1]+ )* )?  # Binary
+			   |  0  ( [0-7]+ ( ' [0-7]+ )* )   # Octal
+			   |     ( [0-9]+ ( ' [0-9]+ )* )   # Decimal
+			   )
+			   ( ([uUfF] | u?ll? | U?LL?)\b | (?&lt;inc&gt;') | \b )
+			|  ( [0-9]+ ( ' [0-9]+ )* )?
+			   (?i:
+			      \. ( [0-9]+ ( ' [0-9]+ )* ) E(\+|-)? ( [0-9]+ ( ' [0-9]+ )* )
+			   |  \. ( [0-9]+ ( ' [0-9]+ )* )
+			   |  E(\+|-)? ( [0-9]+ ( ' [0-9]+ )* )
+			   )
+			   ( (?&lt;inc&gt;') | \b )
+			)</string>
 			<key>name</key>
 			<string>constant.numeric.c</string>
 		</dict>
@@ -381,8 +404,8 @@
 			<string>\b([a-z0-9_]+_t)\b</string>
 			<key>name</key>
 			<string>support.type.posix-reserved.c</string>
-    </dict>
-    <dict>
+		</dict>
+		<dict>
 			<key>include</key>
 			<string>#block</string>
 		</dict>