Cleanup: Spelling Mistakes

This patch fixes many minor spelling mistakes, all in comments or
console output. Mostly contractions like can't, won't, don't, its/it's,
etc.

Differential Revision: https://developer.blender.org/D11663

Reviewed by Harley Acheson

source/blender/makesrna/intern/rna_ui_api.c

@@ -1018,7 +1018,8 @@ void RNA_api_ui_layout(StructRNA *srna)
 
   func = RNA_def_function(srna, "operator_menu_enum", "rna_uiItemMenuEnumO");
   RNA_def_function_flag(func, FUNC_USE_CONTEXT);
-  api_ui_item_op(func); /* cant use api_ui_item_op_common because property must come right after */
+  api_ui_item_op(
+      func); /* can't use api_ui_item_op_common because property must come right after */
   parm = RNA_def_string(func, "property", NULL, 0, "", "Identifier of property in operator");
   RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
   api_ui_item_common(func);