Rich log (#3046)

* log

* tests

* snapshot tests

* change to richlog

* keep raw lines

* disable highlighting by default

* simplify

* superfluous test

* optimization

* update cell length

* add refresh

* write method

* version bump

* doc fix link

* makes lines private

* docstring

* relax dev dependancy

* remove superfluous code [skip ci]

* added FAQ [skipci]

* fix code in faq [skipci]

* fix typo

* max lines fix

docs/examples/widgets/log.py

@@ -0,0 +1,28 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Log
+
+TEXT = """I must not fear.
+Fear is the mind-killer.
+Fear is the little-death that brings total obliteration.
+I will face my fear.
+I will permit it to pass over me and through me.
+And when it has gone past, I will turn the inner eye to see its path.
+Where the fear has gone there will be nothing. Only I will remain."""
+
+
+class LogApp(App):
+    """An app with a simple log."""
+
+    def compose(self) -> ComposeResult:
+        yield Log()
+
+    def on_ready(self) -> None:
+        log = self.query_one(Log)
+        log.write_line("Hello, World!")
+        for _ in range(10):
+            log.write_line(TEXT)
+
+
+if __name__ == "__main__":
+    app = LogApp()
+    app.run()