Typo fixes

+ User facing typos
+ trivial source comment typos
+ superflous double whitespace issues
+ found redundant comment typo
Found using `codespell -q 3 --skip="./build/wix/Localization,./res/translations,./lib" -I ../mixxx-whitelist.txt` where the contents of the whitelist were:
```
iff
freee
substract
```

2 files changed, 2 insertions, 2 deletions

diff --git a/src/util/db/dbconnectionpool.h b/src/util/db/dbconnectionpool.h
index d52e467635..1ecfd8ed51 100644
--- a/src/util/db/dbconnectionpool.h
+++ b/src/util/db/dbconnectionpool.h
@@ -19,7 +19,7 @@ class DbConnectionPool final {
   public:
     // Creates a new pool of database connections (one per thread) that
     // all use the same connection parameters. Unique connection names
-    // will be  generated based on the given connection name that serves
+    // will be generated based on the given connection name that serves
     // as the base name (= common prefix).
     static DbConnectionPoolPtr create(
             const DbConnection::Params& params,
diff --git a/src/util/db/fwdsqlqueryselectresult.cpp b/src/util/db/fwdsqlqueryselectresult.cpp
index 54ab54f857..3543756825 100644
--- a/src/util/db/fwdsqlqueryselectresult.cpp
+++ b/src/util/db/fwdsqlqueryselectresult.cpp
@@ -7,7 +7,7 @@ FwdSqlQuerySelectResult::FwdSqlQuerySelectResult()
 }
 
 // NOTE(uklotzde): The query is passed as an r-value reference to
-// indicate that ownership is transfered. Qt uses implicit sharing
+// indicate that ownership is transferred. Qt uses implicit sharing
 // instead of actually moving the contents of the object. This might
 // be less efficient than actually moving the object's contents, but
 // meets all requirements.