Cleanup: spelling in comments, strings (make check_spelling_*)

Also replace some triple-quoted non-doc-string strings with commented
blocks in examples.

doc/python_api/examples/bpy.app.translations.py

@@ -12,7 +12,7 @@ Introduction
 To add translations to your Python script, you must define a dictionary formatted like that:
 ``{locale: {msg_key: msg_translation, ...}, ...}`` where:
 
-- locale is either a lang iso code (e.g. ``fr``), a lang+country code (e.g. ``pt_BR``),
+- locale is either a lang ISO code (e.g. ``fr``), a lang+country code (e.g. ``pt_BR``),
   a lang+variant code (e.g. ``sr@latin``), or a full code (e.g. ``uz_UZ@cyrilic``).
 - msg_key is a tuple (context, org message) - use, as much as possible, the predefined :const:`contexts`.
 - msg_translation is the translated message in given language!

doc/python_api/examples/bpy.types.FileHandler.1.py

@@ -26,14 +26,14 @@ import bpy
 
 
 class CurveTextImport(bpy.types.Operator):
-    """ Test importer that creates a text object from a .txt file """
+    """
+    Test importer that creates a text object from a text file.
+    """
     bl_idname = "curve.text_import"
     bl_label = "Import a text file as text object"
 
-    """
-    This Operator supports import one .txt file at the time, we need the
-    following filepath property that the file handler will use to set file path data.
-    """
+    # This Operator supports import one `.txt` file at the time, we need the
+    # following file-path property that the file handler will use to set file path data.
     filepath: bpy.props.StringProperty(subtype='FILE_PATH', options={'SKIP_SAVE'})
 
     @classmethod
@@ -41,7 +41,7 @@ class CurveTextImport(bpy.types.Operator):
         return (context.area and context.area.type == "VIEW_3D")
 
     def execute(self, context):
-        """ Calls to this Operator can set unfiltered filepaths, ensure the file extension is .txt. """
+        # Calls to this Operator can set unfiltered file-paths, ensure the file extension is `.txt`.
         if not self.filepath or not self.filepath.endswith(".txt"):
             return {'CANCELLED'}
 
@@ -52,13 +52,11 @@ class CurveTextImport(bpy.types.Operator):
             bpy.context.scene.collection.objects.link(text_object)
         return {'FINISHED'}
 
-    """
-    By default the file handler invokes the operator with the filepath property set.
-    In this example if this property is set the operator is executed, if not the
-    file select window is invoked.
-    This depends on setting ``options={'SKIP_SAVE'}`` to the property options to avoid
-    to reuse filepath data between operator calls.
-    """
+    # By default the file handler invokes the operator with the file-path property set.
+    # In this example if this property is set the operator is executed, if not the
+    # file select window is invoked.
+    # This depends on setting `options={'SKIP_SAVE'}` to the property options to avoid
+    # to reuse file-path data between operator calls.
 
     def invoke(self, context, event):
         if self.filepath:

doc/python_api/examples/bpy.types.UIList.2.py

@@ -108,7 +108,7 @@ class MESH_UL_vgroups_slow(bpy.types.UIList):
 
     def filter_items_empty_vgroups(self, context, vgroups):
         # This helper function checks vgroups to find out whether they are empty, and what's their average weights.
-        # TODO: This should be RNA helper actually (a vgroup prop like "raw_data: ((vidx, vweight), etc.)").
+        # TODO: This should be RNA helper actually (a vgroup prop like `"raw_data: ((vidx, vweight), etc.)"`).
         #       Too slow for Python!
         obj_data = context.active_object.data
         ret = {vg.index: [True, 0.0] for vg in vgroups}
@@ -131,7 +131,7 @@ class MESH_UL_vgroups_slow(bpy.types.UIList):
                         ret[vg.group][0] = False
                         ret[vg.group][1] += vg.weight * fact
         elif hasattr(obj_data, "points"):  # Lattice data
-            # XXX no access to lattice editdata?
+            # XXX: no access to lattice edit-data?
             fact = 1 / len(obj_data.points)
             for v in obj_data.points:
                 for vg in v.groups:
@@ -142,11 +142,11 @@ class MESH_UL_vgroups_slow(bpy.types.UIList):
     def filter_items(self, context, data, propname):
         # This function gets the collection property (as the usual tuple (data, propname)), and must return two lists:
         # * The first one is for filtering, it must contain 32bit integers were self.bitflag_filter_item marks the
-        #   matching item as filtered (i.e. to be shown). The upper 16 bits (including self.bitflag_filter_item) are
+        #   matching item as filtered (i.e. to be shown). The upper 16 bits (including `self.bitflag_filter_item`) are
         #   reserved for internal use, the lower 16 bits are free for custom use. Here we use the first bit to mark
         #   VGROUP_EMPTY.
         # * The second one is for reordering, it must return a list containing the new indices of the items (which
-        #   gives us a mapping org_idx -> new_idx).
+        #   gives us a mapping `org_idx -> new_idx`).
         # Please note that the default UI_UL_list defines helper functions for common tasks (see its doc for more info).
         # If you do not make filtering and/or ordering, return empty list(s) (this will be more efficient than
         # returning full lists doing nothing!).