doc: add style guide (#746)

* doc: add style guide

* doc: style guide for python and markdown

* doc: consistent use of periods and explicit double quotes in style guide

Co-authored-by: Hussein Farran <hmfarran@gmail.com>

* doc: better define string style in style guide

* doc: add format string literals to style guide

* doc: add HTML, CSS and JS to style guide

Co-authored-by: Hussein Farran <hmfarran@gmail.com>

docs/style.md

@@ -0,0 +1,49 @@
+# Style Guide
+
+## Generic
+
+* This guide can be ignored for data files that are not to be viewed in an editor.
+* 120 character per line for all source files.
+* Avoid white space errors like trailing spaces.
+
+
+## Python Code
+
+* We mostly follow [PEP8](https://peps.python.org/pep-0008/). Read below to see the differences.
+* 120 characters per line. PyCharm does this automatically, other editors can be configured for it.
+* Strings in core code will be `"strings"`. In other words: double quote your strings.
+* Strings in worlds should use double quotes as well, but imported code may differ.
+* Prefer [format string literals](https://peps.python.org/pep-0498/) over string concatenation,
+  use single quotes inside them: `f"Like {dct['key']}"`
+* Use type annotation where possible.
+
+
+## Markdown
+
+* We almost follow [Google's styleguide](https://google.github.io/styleguide/docguide/style.html).
+  Read below for differences.
+* For existing documents, try to follow its style or ask to completely reformat it.
+* 120 characters per line.
+* One space between bullet/number and text.
+* No lazy numbering.
+
+
+## HTML
+
+* Indent with 2 spaces for new code.
+* kebab-case for ids and classes.
+
+
+## CSS
+
+* Indent with 2 spaces for new code.
+* `{` on the same line as the selector.
+* No space between selector and `{`.
+
+
+## JS
+
+* Indent with 2 spaces.
+* Indent `case` inside `switch ` with 2 spaces.
+* Use single quotes.
+* Semicolons are required after every statement.

docs/world api.md

@@ -236,7 +236,7 @@ class MyGameLocation(Location):
     game: str = "My Game"
 
     # override constructor to automatically mark event locations as such
-    def __init__(self, player: int, name = '', code = None, parent = None):
+    def __init__(self, player: int, name = "", code = None, parent = None):
         super(MyGameLocation, self).__init__(player, name, code, parent)
         self.event = code is None
 ```
@@ -487,14 +487,14 @@ def create_items(self) -> None:
     for item in map(self.create_item, mygame_items):
         if item in exclude:
             exclude.remove(item)  # this is destructive. create unique list above
-            self.world.itempool.append(self.create_item('nothing'))
+            self.world.itempool.append(self.create_item("nothing"))
         else:
             self.world.itempool.append(item)
 
     # itempool and number of locations should match up.
     # If this is not the case we want to fill the itempool with junk.
     junk = 0  # calculate this based on player settings
-    self.world.itempool += [self.create_item('nothing') for _ in range(junk)]
+    self.world.itempool += [self.create_item("nothing") for _ in range(junk)]
 ```
 
 #### create_regions
@@ -628,7 +628,7 @@ class MyGameLogic(LogicMixin):
     def _mygame_has_key(self, world: MultiWorld, player: int):
         # Arguments above are free to choose
         # it may make sense to use World as argument instead of MultiWorld
-        return self.has('key', player)  # or whatever
+        return self.has("key", player)  # or whatever
 ```
 ```python
 # __init__.py