logcheck: harmonize report messages

If the message consists of full sentences, it should use valid spelling (upper
capital at the beginning, full stop at the end). Shorter messages should be
consistent with messages from other tools where lower case seems to be more
common (https://grep.app/search?q=pass.Report).

hack/tools/logcheck/pkg/logcheck.go

@@ -331,14 +331,14 @@ func isKeysValid(keyValues []ast.Expr, fun ast.Expr, pass *analysis.Pass, funNam
 		if !ok {
 			pass.Report(analysis.Diagnostic{
 				Pos:     fun.Pos(),
-				Message: fmt.Sprintf("Key positional arguments are expected to be inlined constant strings. Please replace %v provided with string value", arg),
+				Message: fmt.Sprintf("Key positional arguments are expected to be inlined constant strings. Please replace %v provided with string value.", arg),
 			})
 			continue
 		}
 		if lit.Kind != token.STRING {
 			pass.Report(analysis.Diagnostic{
 				Pos:     fun.Pos(),
-				Message: fmt.Sprintf("Key positional arguments are expected to be inlined constant strings. Please replace %v provided with string value", lit.Value),
+				Message: fmt.Sprintf("Key positional arguments are expected to be inlined constant strings. Please replace %v provided with string value.", lit.Value),
 			})
 			continue
 		}
@@ -483,7 +483,7 @@ func checkForIfEnabled(i *ast.IfStmt, pass *analysis.Pass, c *config) {
 	pass.Report(analysis.Diagnostic{
 		Pos: i.Pos(),
 		End: i.End(),
-		Message: fmt.Sprintf("The result of %s should be stored in a variable and then be used multiple times: if %s := %s(); %s.Enabled() { ... %s.Info ... }",
+		Message: fmt.Sprintf("the result of %s should be stored in a variable and then be used multiple times: if %s := %s(); %s.Enabled() { ... %s.Info ... }",
 			funcCall, varName, funcCall, varName, varName),
 	})
 }