void setSize(int charCount) {
		width = charCount * charWidth;
		// add in space for margins
		width += 2 * charWidth;

		noValueStr = StringUtils.repeat('.', charCount);
	}
Sets the size of this field based on the number of chars to display 
@param charCount the number of chars to
Ghidra/Features/ByteViewer/src/main/java/ghidra/app/plugin/core/byteviewer/IndexFieldFactory.java