PHP 8.2 | Tokenizer/PHP: add support for DNF types

[jrfnl]

Description

This commit adds tokenizer support for DNF types as per the proposal outlined in #387.

This means that:

• Two new tokens are introduced T_TYPE_OPEN_PARENTHESIS and T_TYPE_CLOSE_PARENTHESIS for the parentheses used in DNF types. This allows for sniffs to specifically target those tokens and prevents sniffs which are looking for the "normal" open/close parenthesis tokens from acting on DNF parentheses.
• These new tokens, like other parentheses, will get the parenthesis_opener and parenthesis_closer token array indexes and the tokens between them will have the nested_parenthesis index.

Based on the currently added tests, the commit safeguards that:

• The | in types is still tokenized as T_TYPE_UNION, even in DNF types.
• The & in types is still tokenized as T_TYPE_INTERSECTION, even in DNF types.
• The static keyword for properties is still tokenized as T_STATIC, even when right before a DNF type (which could be confused for a function call).
• The arrow function retokenization to T_FN with a T_FN_ARROW scope opener is handled correctly, even when DNF types are involved and including when the arrow function is declared to return by reference.
• The keyword tokens, like self, parent, static, true or false, when used in DNF types are still tokenized to their own token and not tokenized as T_STRING.
• The array keyword when used in DNF types is still tokenized as T_STRING and not as T_ARRAY.
• A ? intended as an (illegal) nullability operator in combination with a DNF type is still tokenized as T_NULLABLE and not as T_INLINE_THEN.
• A function declaration open parenthesis before a typed parameter isn't accidentally retokenized to T_TYPE_OPEN_PARENTHESIS.

Includes ample unit tests.

Even so, strenuous testing of this PR is recommended as there are so many moving parts involved, it is very easy for something to have been overlooked.

Suggested changelog entry

Added: tokenizer support for Disjunctive Normal Form types.

Related issues/external references

Related to #105

Closes #387
Closes squizlabs/PHP_CodeSniffer#3731

Types of changes

• New feature (non-breaking change which adds functionality)

[jrfnl]

Rebased without changes.

Even though there has been no feedback so far, I am going to merge this PR to improve the chances of people using the master branch testing this change in hopes of any undesired side-effects being caught before the next release.