Misc. typo fixes

Found via `codespell -q 3 -S *.ts,./3rd-party -L ba,childs,iff,nd,uint`

course_design.md

@@ -8,7 +8,7 @@ keywords: Courses, Symbol sets
 
 OpenOrienteering Mapper doesn't have a sophisticated course planning feature.
 The Course Design symbol set provides basic support for designing maps with
-courses and control desriptions. It contains the overprinting symbols from the
+courses and control descriptions. It contains the overprinting symbols from the
 ISOM 2000 and the control descriptions from IOF's "International Specification
 for Control Descriptions - 2004". See the [IOF Homepage] for details.
 
@@ -50,7 +50,7 @@ the nearest 0.1 km. The height climb is given in metres rounded to the nearest
 
 The heading is followed by lines describing the start location, the individual
 controls, and special routes. The description of start and individual controls
-uses eight colums which are refered to as A...H.
+uses eight columns which are referred to as A...H.
 
 | Column | Description |
 | ------ | ----------- |

faq.md

@@ -43,7 +43,7 @@ With the [line edit tool](toolbars.md#tool_edit_line), select the object you wan
 
 ### How can I cut out a part of a map to take it for a new map?
 
-First you save the map to the new file. Then draw some closed line or area (symbol doesn't matter) arround the border of the part which you want to keep. Now when this border object is finished and selected, click on the "Cutout" icon or menu item, then press the enter key.
+First you save the map to the new file. Then draw some closed line or area (symbol doesn't matter) around the border of the part which you want to keep. Now when this border object is finished and selected, click on the "Cutout" icon or menu item, then press the enter key.
 
 
 ## File formats

symbol_dock_widget.md

@@ -42,7 +42,7 @@ To show the symbol menu, right click the symbol pane:
 
  - The actions in the first section enable to create new symbols or edit the selected symbol.
  - The actions in the second section enable to copy/paste symbols.
- - In the third section, in additon to the possibility to select all symbols with the selected object, there are shortcuts to the two drawing functions [switch symbol](toolbars.md#switch_symbol) and [fill / create border](toolbars.md#fill_create_border).
+ - In the third section, in addition to the possibility to select all symbols with the selected object, there are shortcuts to the two drawing functions [switch symbol](toolbars.md#switch_symbol) and [fill / create border](toolbars.md#fill_create_border).
  - The fourth section enables to hide all objects with a given symbol, for example to remove all paths from a map, and to protect all objects with a given symbol from editing. This is useful to make large area symbols static while editing other objects on top of them.
  - The last section offers actions for symbol selection and sorting.
 

symbols_menu.md

@@ -25,7 +25,7 @@ This toggle switches the display of the [color window](color_dock_widget.md) on
 #### Symbol set ID...
 
 Opens a dialog for changing the map's symbol set ID.
-The symbol set ID controls suggested symbol replacements during import and during explict map symbol set replacment.
+The symbol set ID controls suggested symbol replacements during import and during explicit map symbol set replacment.
 
 
 #### Scale all symbols...