fix(lexer): fix inproper handling of \\\n

Before it would escape the newline resulting in passing it as an
argument.

Signed-off-by: Charlotte Meyer <dev@buffet.sh>

crates/oyster_parser/src/lexer.rs

@@ -125,10 +125,10 @@ impl Lexer<'_> {
                         TokenKind::Comment
                     }
 
-                    '\\' => {
-                        self.next_char();
-                        TokenKind::EscapedChar
-                    }
+                    '\\' => match self.next_char() {
+                        Some('\n') => TokenKind::Whitespace,
+                        _ => TokenKind::EscapedChar,
+                    },
 
                     _ => {
                         self.eat_while(|c| {

crates/oyster_parser/tests/it/lexer.rs

@@ -144,3 +144,12 @@ fn closing_parenthesis_string_mode() {
 
     assert_snapshot!(actual);
 }
+
+#[test]
+fn escape_newline() {
+    let source = "\\\n";
+
+    let actual = Lexer::new(source).next_command_token();
+
+    assert_snapshot!(actual);
+}

crates/oyster_parser/tests/it/snapshots/it__lexer__escape_newline.snap

@@ -0,0 +1,8 @@
+---
+source: crates/oyster_parser/tests/it/lexer.rs
+expression: actual
+---
+Token {
+    kind: Whitespace,
+    len: 2,
+}