Remove column 1 restriction for labels with colons (#635)

Partial fix for #457

src/asm/lexer.c

@@ -2026,7 +2026,7 @@ static int yylex_NORMAL(void)
 					}
 				}
 
-				if (tokenType == T_ID && lexerState->atLineStart)
+				if (tokenType == T_ID && (lexerState->atLineStart || peek(0) == ':'))
 					return T_LABEL;
 
 				return tokenType;

test/asm/label-indent.asm

@@ -0,0 +1,30 @@
+
+SECTION "Label testing", WRAMX
+
+	Lab:
+	.loc
+	Lab.loc2
+
+;	X = 0
+;	; Should not believe X is a label!
+;	IF X == 1
+;		FAIL "Wrong!"
+;	ENDC
+;	X \
+;	  = 1
+;	IF X != 1
+;		FAIL "Wrong!"
+;	ENDC
+;
+;	Y equ 42
+;	PRINTT "Y={Y}\n"
+;	PURGE Y
+;
+;	Y equs "mac"
+;	mac: MACRO
+;		PRINTT "\1\n"
+;	ENDM
+;	; Should invoke macro Y, and not match "equ" due to the "a" behind it
+;	Y equates 69
+;	Y equsquisite (isn't that English?)
+;	Y eq