php8: fixed a bug with # comments (#22)

Example from issue:
```php
<?php
#
# Comment
#

$a = 100;
```

The problem with the example from the issue is that `#` is immediately followed by a line break.
And since the rule in the lexer for such comments was changed, this case was handled incorrectly.

```
(('#' ^'[') | '//') any_line* when is_not_comment_end => {
   lex.ungetStr("?>")
   lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
};
```

This rule has one problem, it checks two characters at once, first for the match `#`, and 
then for the mismatch `[`, which leads to the fact that in the case of an empty comment, the first 
matcher will capture `#`, and the second line break (`\n`), which will lead to the fact that `any_line` 
matcher will not work and will not increase the line number.

The next rule added is specifically for this case.

```
'#' newline when is_not_comment_end => {
    lex.ungetStr("?>")
    lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
};
```

internal/php8/scanner.rl

@@ -336,13 +336,21 @@ func (lex *Lexer) Lex() *token.Token {
             '(' whitespace* ('string'i|'binary'i) whitespace* ')'        => {lex.setTokenPosition(tkn); tok = token.T_STRING_CAST; fbreak;};
             '(' whitespace* 'unset'i whitespace* ')'                     => {lex.error(fmt.Sprintf("The (unset) cast is no longer supported")); fbreak;};
 
+            # For case '#\n'
+            '#' newline when is_not_comment_end => {
+                lex.ungetStr("?>")
+                lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
+            };
+
             (('#' ^'[') | '//') any_line* when is_not_comment_end => {
                 lex.ungetStr("?>")
                 lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
             };
+
             '#' => {
                 lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
             };
+
             '/*' any_line* :>> '*/' {
                 isDocComment := false;
                 if lex.te - lex.ts > 4 && string(lex.data[lex.ts:lex.ts+3]) == "/**" {

internal/php8/scanner_php8_test.go

@@ -6,6 +6,7 @@ import (
 	"github.com/VKCOM/php-parser/internal/php8"
 	"github.com/VKCOM/php-parser/internal/tester"
 	"github.com/VKCOM/php-parser/pkg/conf"
+	"github.com/VKCOM/php-parser/pkg/position"
 	"github.com/VKCOM/php-parser/pkg/token"
 	"gotest.tools/assert"
 )
@@ -344,3 +345,62 @@ func TestNamespaceRelativeTokens(t *testing.T) {
 	}
 	suite.Run()
 }
+
+func TestSharpCommentTokens(t *testing.T) {
+	suite := tester.NewLexerTokenStructTestSuite(t)
+	suite.UsePHP8()
+	suite.WithPosition()
+	suite.WithFreeFloating()
+	suite.Code = `<?php
+#
+# Hello
+#
+
+$a;
+`
+	suite.Expected = []*token.Token{
+		{
+			ID:    php8.T_VARIABLE,
+			Value: []byte(`$a`),
+			FreeFloating: []*token.Token{
+				{
+					ID:       php8.T_OPEN_TAG,
+					Value:    []byte("<?php"),
+					Position: &position.Position{StartLine: 1, EndLine: 1, EndPos: 5},
+				},
+				{
+					ID:       php8.T_WHITESPACE,
+					Value:    []byte("\n"),
+					Position: &position.Position{StartLine: 1, EndLine: 1, StartPos: 5, EndPos: 6},
+				},
+				{
+					ID:       php8.T_COMMENT,
+					Value:    []byte("#\n"),
+					Position: &position.Position{StartLine: 2, EndLine: 2, StartPos: 6, EndPos: 8},
+				},
+				{
+					ID:       php8.T_COMMENT,
+					Value:    []byte("# Hello\n"),
+					Position: &position.Position{StartLine: 3, EndLine: 3, StartPos: 8, EndPos: 16},
+				},
+				{
+					ID:       php8.T_COMMENT,
+					Value:    []byte("#\n"),
+					Position: &position.Position{StartLine: 4, EndLine: 4, StartPos: 16, EndPos: 18},
+				},
+				{
+					ID:       php8.T_WHITESPACE,
+					Value:    []byte("\n"),
+					Position: &position.Position{StartLine: 5, EndLine: 5, StartPos: 18, EndPos: 19},
+				},
+			},
+			Position: &position.Position{StartLine: 6, EndLine: 6, StartPos: 19, EndPos: 21},
+		},
+		{
+			ID:       ';',
+			Value:    []byte(";"),
+			Position: &position.Position{StartLine: 6, EndLine: 6, StartPos: 21, EndPos: 22},
+		},
+	}
+	suite.Run()
+}

internal/tester/lexer_token_struct.go

@@ -18,6 +18,9 @@ type LexerTokenStructTestSuite struct {
 	Expected []*token.Token
 
 	Version version.Version
+
+	withPosition     bool
+	withFreeFloating bool
 }
 
 func NewLexerTokenStructTestSuite(t *testing.T) *LexerTokenStructTestSuite {
@@ -34,6 +37,14 @@ func (l *LexerTokenStructTestSuite) UsePHP8() {
 	l.Version = version.Version{Major: 8, Minor: 0}
 }
 
+func (l *LexerTokenStructTestSuite) WithPosition() {
+	l.withPosition = true
+}
+
+func (l *LexerTokenStructTestSuite) WithFreeFloating() {
+	l.withFreeFloating = true
+}
+
 func (l *LexerTokenStructTestSuite) Run() {
 	config := conf.Config{
 		Version: &l.Version,
@@ -49,8 +60,12 @@ func (l *LexerTokenStructTestSuite) Run() {
 
 	for _, expected := range l.Expected {
 		actual := lexer.Lex()
-		actual.Position = nil
-		actual.FreeFloating = nil
+		if !l.withPosition {
+			actual.Position = nil
+		}
+		if !l.withFreeFloating {
+			actual.FreeFloating = nil
+		}
 		assert.DeepEqual(l.t, expected, actual)
 	}
 }