fixed typos and some linter suggestions

tools/search/filter.go

@@ -635,7 +635,7 @@ func multiMatchAfterBuildFunc(op fexpr.SignOp, multiMatchAliases ...string) func
 		// Add an optional "IS NULL" condition(s) to handle the empty rows result.
 		//
 		// For example, let's assume that some "rel" field is [nonemptyRel1, nonemptyRel2, emptyRel3],
-		// The filter "rel.total > 0" will ensures that the above will return true only if all relations
+		// The filter "rel.total > 0" ensures that the above will return true only if all relations
 		// are existing and match the condition.
 		//
 		// The "=" operator is excluded because it will never equal directly with NULL anyway

tools/search/provider.go

@@ -81,7 +81,7 @@ func (s *Provider) SkipTotal(skipTotal bool) *Provider {
 }
 
 // CountCol allows changing the default column (id) that is used
-// to generated the COUNT SQL query statement.
+// to generate the COUNT SQL query statement.
 //
 // This field is ignored if skipTotal is true.
 func (s *Provider) CountCol(name string) *Provider {