Use std::vector for capture buffer

include/asm/lexer.hpp

@@ -6,6 +6,7 @@
 #include <deque>
 #include <optional>
 #include <string>
+#include <vector>
 
 #include "platform.hpp" // SSIZE_MAX
 
@@ -82,8 +83,7 @@ struct LexerState {
 
 	bool capturing; // Whether the text being lexed should be captured
 	size_t captureSize; // Amount of text captured
-	char *captureBuf; // Buffer to send the captured text to if non-null
-	size_t captureCapacity; // Size of the buffer above
+	std::vector<char> *captureBuf; // Buffer to send the captured text to if non-null
 
 	bool disableMacroArgs;
 	bool disableInterpolation;