doc: Correct spelling errors in comments

And ci script output.

Identified via test/lint/lint-spelling

test/lint/lint-shell.sh

@@ -41,7 +41,7 @@ if ! shellcheck "$EXCLUDE" $(git ls-files -- '*.sh' | grep -vE 'src/(leveldb|sec
 fi
 
 if ! command -v yq > /dev/null; then
-    echo "Skipping Gitian desriptor scripts checking since yq is not installed."
+    echo "Skipping Gitian descriptor scripts checking since yq is not installed."
     exit $EXIT_CODE
 fi
 

test/lint/lint-spelling.ignore-words.txt

@@ -12,3 +12,5 @@ keyserver
 homogenous
 setban
 hist
+ser
+unselect