enabled strict PHPStan analysis parameters

Added 9 strict analysis parameters to extension.neon to enforce stricter
type checking in Nette libraries: callable signatures, function/class name
casing, nullable types in signatures and PHPDocs, redundant conditions,
and @var tag validation.

Author: dg

extension.neon

@@ -1,4 +1,13 @@
 parameters:
+	checkMissingCallableSignature: true
+	checkFunctionNameCase: true
+	checkInternalClassCaseSensitivity: true
+	reportMaybesInMethodSignatures: true
+	reportMaybesInPropertyPhpDocTypes: true
+	reportStaticMethodSignatures: true
+	reportAlwaysTrueInLastCondition: true
+	reportWrongPhpDocTypeInVarTag: true
+	reportAnyTypeWideningInVarTag: true
 
 	fileExtensions:
 		- php