scanner: fix err pos related to num literals

vlib/v/checker/tests/bin_lit_without_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/bin_lit_without_digit_err.v:2:14: error: number part of this binary is not provided
+    1 | fn main() {
+    2 |     println(0b)
+      |              ^
+    3 | }

vlib/v/checker/tests/bin_lit_without_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0b)
+}

vlib/v/checker/tests/bin_lit_wrong_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/bin_lit_wrong_digit_err.v:2:18: error: this binary number has unsuitable digit `2`
+    1 | fn main() {
+    2 |     println(0b1112)
+      |                  ^
+    3 | }

vlib/v/checker/tests/bin_lit_wrong_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0b1112)
+}

vlib/v/checker/tests/dec_lit_wrong_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/dec_lit_wrong_digit_err.v:2:18: error: this number has unsuitable digit `q`
+    1 | fn main() {
+    2 |     println(12345q)
+      |                  ^
+    3 | }

vlib/v/checker/tests/dec_lit_wrong_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(12345q)
+}

vlib/v/checker/tests/float_lit_exp_not_integer_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/float_lit_exp_not_integer_err.v:2:17: error: exponential part should be integer
+    1 | fn main() {
+    2 |     println(45e2.5)
+      |                 ^
+    3 | }

vlib/v/checker/tests/float_lit_exp_not_integer_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(45e2.5)
+}

vlib/v/checker/tests/float_lit_exp_without_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/float_lit_exp_without_digit_err.v:2:14: error: exponent has no digits
+    1 | fn main() {
+    2 |     println(2E)
+      |              ^
+    3 | }

vlib/v/checker/tests/float_lit_exp_without_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(2E)
+}

vlib/v/checker/tests/float_lit_too_many_points_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/float_lit_too_many_points_err.v:2:19: error: too many decimal points in number
+    1 | fn main() {
+    2 |     println(123.45.67)
+      |                   ^
+    3 | }

vlib/v/checker/tests/float_lit_too_many_points_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(123.45.67)
+}

vlib/v/checker/tests/hex_lit_without_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/hex_lit_without_digit_err.v:2:14: error: number part of this hexadecimal is not provided
+    1 | fn main() {
+    2 |     println(0x)
+      |              ^
+    3 | }

vlib/v/checker/tests/hex_lit_without_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0x)
+}

vlib/v/checker/tests/hex_lit_wrong_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/hex_lit_wrong_digit_err.v:2:18: error: this hexadecimal number has unsuitable digit `g`
+    1 | fn main() {
+    2 |     println(0x111g)
+      |                  ^
+    3 | }

vlib/v/checker/tests/hex_lit_wrong_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0x111g)
+}

vlib/v/checker/tests/oct_lit_without_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/oct_lit_without_digit_err.v:2:14: error: number part of this octal is not provided
+    1 | fn main() {
+    2 |     println(0o)
+      |              ^
+    3 | }

vlib/v/checker/tests/oct_lit_without_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0o)
+}

vlib/v/checker/tests/oct_lit_wrong_digit_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/oct_lit_wrong_digit_err.v:2:18: error: this octal number has unsuitable digit `8`
+    1 | fn main() {
+    2 |     println(0o1118)
+      |                  ^
+    3 | }

vlib/v/checker/tests/oct_lit_wrong_digit_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+    println(0o1118)
+}

vlib/v/scanner/scanner.v

@@ -174,9 +174,11 @@ fn (mut s Scanner) ident_bin_number() string {
 		s.pos++
 	}
 	if start_pos + 2 == s.pos {
+		s.pos-- // adjust error position
 		s.error('number part of this binary is not provided')
 	}
 	else if has_wrong_digit {
+		s.pos-- // adjust error position
 		s.error('this binary number has unsuitable digit `${first_wrong_digit.str()}`')
 	}
 	number := filter_num_sep(s.text.str, start_pos, s.pos)
@@ -203,9 +205,11 @@ fn (mut s Scanner) ident_hex_number() string {
 		s.pos++
 	}
 	if start_pos + 2 == s.pos {
+		s.pos-- // adjust error position
 		s.error('number part of this hexadecimal is not provided')
 	}
 	else if has_wrong_digit {
+		s.pos-- // adjust error position
 		s.error('this hexadecimal number has unsuitable digit `${first_wrong_digit.str()}`')
 	}
 	number := filter_num_sep(s.text.str, start_pos, s.pos)
@@ -232,9 +236,11 @@ fn (mut s Scanner) ident_oct_number() string {
 		s.pos++
 	}
 	if start_pos + 2 == s.pos {
+		s.pos-- // adjust error position
 		s.error('number part of this octal is not provided')
 	}
 	else if has_wrong_digit {
+		s.pos-- // adjust error position
 		s.error('this octal number has unsuitable digit `${first_wrong_digit.str()}`')
 	}
 	number := filter_num_sep(s.text.str, start_pos, s.pos)
@@ -335,10 +341,12 @@ fn (mut s Scanner) ident_dec_number() string {
 	}
 	if has_wrong_digit {
 	// error check: wrong digit
+		s.pos-- // adjust error position
 		s.error('this number has unsuitable digit `${first_wrong_digit.str()}`')
 	}
 	else if s.text[s.pos - 1] in [`e`, `E`] {
 	// error check: 5e
+		s.pos-- // adjust error position
 		s.error('exponent has no digits')
 	}
 	else if s.pos < s.text.len && s.text[s.pos] == `.` && !is_range && !is_float_without_fraction && !call_method {