Update README and .gitignore

Author: mdbrnowski

.gitignore

@@ -1,3 +1,9 @@
-.antlr/
+# Editor
 .vscode/
-__pycache__/
+.antlr/
+
+# Python
+__pycache__/
+.pytest_cache/
+.ruff_cache/
+.venv/

README.md

@@ -2,21 +2,11 @@
 
 [![actions status](https://github.com/mdbrnowski/linalg-language/actions/workflows/test.yml/badge.svg)](https://github.com/mdbrnowski/linalg-language/actions)
 
-To generate lexer and parser in Python, run
+To explore all available commands, simply run `./main.py`.
+
+If you want to generate lexer and parser yourself (for some reason), run
 
 ```bash
 antlr4 -o generated -Dlanguage=Python3 MyLexer.g4
 antlr4 -o generated -Dlanguage=Python3 MyParser.g4
 ```
-
-To use lexer on `example.txt`, run
-
-```bash
-./main.py lex example.txt
-```
-
-To use parser on `example.txt`, run
-
-```bash
-./main.py parse example.txt
-```