*: shellcheck and fix typos (#6526)

* test.sh: quote a variable

* contributing-guides/*: fix typos

* pages/*: fix typos

* scripts/*: fix typos

* MAINTAINERS.md: trim trailing whitespace

Co-authored-by: a1346054 <36859588+a1346054@users.noreply.github.com>

pages/common/az-vm.md

@@ -4,7 +4,7 @@
 > Part of `az`, the command-line client for Microsoft Azure.
 > More information: <https://docs.microsoft.com/cli/azure/vm>.
 
-- List details of availible Virtual Machines:
+- List details of available Virtual Machines:
 
 `az vm list`
 
@@ -28,6 +28,6 @@
 
 `az vm restart --resource-group {{rg}} --name {{vm_name}}`
 
-- List VM images availiable in the Azure Marketplace:
+- List VM images available in the Azure Marketplace:
 
 `az vm image list`

pages/common/git-summary.md

@@ -16,6 +16,6 @@
 
 `git summary --dedup-by-email`
 
-- Display data about a Git repository, showing the number of lines modified by each contributer:
+- Display data about a Git repository, showing the number of lines modified by each contributor:
 
 `git summary --line`

pages/common/pio-platform.md

@@ -21,7 +21,7 @@
 
 - Update installed development platforms:
 
-`pio platfom update`
+`pio platform update`
 
 - Uninstall a development platform:
 

pages/common/tlmgr-paper.md

@@ -15,7 +15,7 @@
 
 `tlmgr {{pdftex}} paper`
 
-- Set the dafault paper size for a specific TeX Live program to A4:
+- Set the default paper size for a specific TeX Live program to A4:
 
 `sudo tlmgr {{pdftex}} paper {{a4}}`