[exec.envs] Fix typo

Author: Andreas-Krug

source/exec.tex

@@ -4982,7 +4982,7 @@
 of all the \tcode{completion_signatures} specializations in the set
 \tcode{AdditionalSignatures}, \tcode{Vs...}, \tcode{Es...}, \tcode{Ss}.
 
-\rSec1[exec.envs]{Queryable uilities}
+\rSec1[exec.envs]{Queryable utilities}
 
 \rSec2[exec.prop]{Class template \tcode{prop}}