Changed all occurrences of 'charcter' found by git grep. All of them
were used in comments only, so it should not break anything.

Change-Id: Ief2c00d929ae7972c55a4920fc0eaa8d6b18ab82
Reviewed-on: https://gerrit.libreoffice.org/2372Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>