Fix typos in tutorial.ipynb (#1378)

docs/source/tutorial.ipynb

@@ -10,7 +10,7 @@
     "Parsing and Visiting\n",
     "====================\n",
     "\n",
-    "LibCST provides helpers to parse source code string as concrete syntax tree. In order to perform static analysis to identify patterns in the tree or modify the tree programmatically, we can use visitor pattern to traverse the tree. In this tutorial, we demonstrate a common four-step-workflow to build an automated refactoring (codemod) application:\n",
+    "LibCST provides helpers to parse source code string as a concrete syntax tree. In order to perform static analysis to identify patterns in the tree or modify the tree programmatically, we can use the visitor pattern to traverse the tree. In this tutorial, we demonstrate a common four-step-workflow to build an automated refactoring (codemod) application:\n",
     "\n",
     "1. `Parse Source Code <#Parse-Source-Code>`_\n",
     "2. `Display The Source Code CST <#Display-Source-Code-CST>`_\n",
@@ -19,7 +19,7 @@
     "\n",
     "Parse Source Code\n",
     "=================\n",
-    "LibCST provides various helpers to parse source code as concrete syntax tree: :func:`~libcst.parse_module`, :func:`~libcst.parse_expression` and :func:`~libcst.parse_statement` (see :doc:`Parsing <parser>` for more detail)."
+    "LibCST provides various helpers to parse source code as a concrete syntax tree: :func:`~libcst.parse_module`, :func:`~libcst.parse_expression` and :func:`~libcst.parse_statement` (see :doc:`Parsing <parser>` for more detail)."
    ]
   },
   {
@@ -90,7 +90,7 @@
     "|\n",
     "Example: add typing annotation from pyi stub file to Python source\n",
     "------------------------------------------------------------------\n",
-    "Python `typing annotation <https://mypy.readthedocs.io/en/latest/cheat_sheet_py3.html>`_ was added in Python 3.5. Some Python applications add typing annotations in separate ``pyi`` stub files in order to support old Python versions. When applications decide to stop supporting old Python versions, they'll want to automatically copy the type annotation from a pyi file to a source file. Here we demonstrate how to do that easliy using LibCST. The first step is to parse the pyi stub and source files as trees."
+    "Python `typing annotation <https://mypy.readthedocs.io/en/latest/cheat_sheet_py3.html>`_ was added in Python 3.5. Some Python applications add typing annotations in separate ``pyi`` stub files in order to support old Python versions. When applications decide to stop supporting old Python versions, they'll want to automatically copy the type annotation from a pyi file to a source file. Here we demonstrate how to do that easily using LibCST. The first step is to parse the pyi stub and source files as trees."
    ]
   },
   {
@@ -106,7 +106,7 @@
     "                self._replace(type=self.type.name))\n",
     "\n",
     "def tokenize(code, version_info, start_pos=(1, 0)):\n",
-    "    \"\"\"Generate tokens from a the source code (string).\"\"\"\n",
+    "    \"\"\"Generate tokens from the source code (string).\"\"\"\n",
     "    lines = split_lines(code, keepends=True)\n",
     "    return tokenize_lines(lines, version_info, start_pos=start_pos)\n",
     "'''\n",
@@ -134,7 +134,7 @@
     "Build Visitor or Transformer\n",
     "============================\n",
     "For traversing and modifying the tree, LibCST provides Visitor and Transformer classes similar to the `ast module <https://docs.python.org/3/library/ast.html#ast.NodeVisitor>`_. To implement a visitor (read only) or transformer (read/write), simply implement a subclass of :class:`~libcst.CSTVisitor` or :class:`~libcst.CSTTransformer` (see :doc:`Visitors <visitors>` for more detail).\n",
-    "In the typing example, we need to implement a visitor to collect typing annotation from the stub tree and a transformer to copy the annotation to the function signature. In the visitor, we implement ``visit_FunctionDef`` to collect annotations. Later in the transformer, we implement ``leave_FunctionDef`` to add the collected annotations."
+    "In the typing example, we need to implement a visitor to collect typing annotations from the stub tree and a transformer to copy the annotation to the function signature. In the visitor, we implement ``visit_FunctionDef`` to collect annotations. Later in the transformer, we implement ``leave_FunctionDef`` to add the collected annotations."
    ]
   },
   {
@@ -226,7 +226,7 @@
     "|\n",
     "Generate Source Code\n",
     "====================\n",
-    "Generating the source code from a cst tree is as easy as accessing the :attr:`~libcst.Module.code` attribute on :class:`~libcst.Module`. After the code generation, we often use `ufmt <https://ufmt.omnilib.dev/en/stable/>`_ to reformate the code to keep a consistent coding style."
+    "Generating the source code from a cst tree is as easy as accessing the :attr:`~libcst.Module.code` attribute on :class:`~libcst.Module`. After the code generation, we often use `ufmt <https://ufmt.omnilib.dev/en/stable/>`_ to reformat the code to keep a consistent coding style."
    ]
   },
   {