Support file-level type: ignore comments (#15081)

crates/red_knot_python_semantic/resources/mdtest/suppressions/knot-ignore.md

@@ -118,3 +118,15 @@ An empty codes array suppresses no-diagnostics and is always useless
 # error: [division-by-zero]
 a = 4 / 0  # knot: ignore[]
 ```
+
+## File-level suppression comments
+
+File level suppression comments are currently intentionally unsupported because we've yet to decide
+if they should use a different syntax that also supports enabling rules or changing the rule's
+severity: `knot: possibly-undefined-reference=error`
+
+```py
+# knot: ignore[division-by-zero]
+
+a = 4 / 0  # error: [division-by-zero]
+```

crates/red_knot_python_semantic/resources/mdtest/suppressions/type-ignore.md

@@ -122,3 +122,36 @@ a = (  # type: ignore
     test + 4  # error: [unresolved-reference]
 )
 ```
+
+## File level suppression
+
+```py
+# type: ignore
+
+a = 10 / 0
+b = a / 0
+```
+
+## File level suppression with leading shebang
+
+```py
+#!/usr/bin/env/python
+# type: ignore
+
+a = 10 / 0
+b = a / 0
+```
+
+## Invalid own-line suppression
+
+```py
+"""
+File level suppressions must come before any non-trivia token,
+including module docstrings. 
+"""
+
+# type: ignore
+
+a = 10 / 0  # error: [division-by-zero]
+b = a / 0  # error: [division-by-zero]
+```