Bump phan/phan from 2.3.0 to 2.3.1

[dependabot-preview]

Bumps phan/phan from 2.3.0 to 2.3.1.

Changelog

Sourced from phan/phan's changelog.

Oct 20 2019, Phan 2.3.1

New features(CLI, Configs):

• Instead of printing the full help when Phan CLI args or configuration is invalid,
  print just the errors/warnings and instructions and Type ./phan --help (or --extended-help) for usage.
• Add an option --debug-signal-handler that can be used to diagnose
  why Phan or a plugin is slow or hanging. (Requires the pcntl module)
  This installs a signal handler that response to SIGINT (aka Ctrl-C), SIGUSR1, and SIGUSR2.
• Print a single backtrace in the crash reporter with the file, line, and arguments instead of multiple backtraces.
• Emit a warning suggesting using --long-option instead when -long-option[=value] is passed in.
• Change colorization of some error messages. Print some warnings to stderr instead of using error_log().

New features(Analysis):

• Emit PhanTypeMismatchPropertyRealByRef or PhanTypeMismatchPropertyByRef
  when potentially assigning an incompatible type to a php 7.4 typed property
  (or a property with a phpdoc type).

• Warn about suspicious uses of + or += on array shapes or lists. (#3364)
  These operator will prefer the fields from the left hand side,
  and will merge lists instead of concatenate them.
  New issue types: PhanSuspiciousBinaryAddLists, PhanUselessBinaryAddRight

• Improvements to inferred types of sort, array_merge, etc. (#3354)

• Fix bug allowing any array shape type to cast to a list.

• Warn about unnecessary branches leading to identical return statements in pure functions, methods, and closures (#3383)
  This check is only run on pure methods.

  This requires that UseReturnValuePlugin be enabled and works best when 'plugin_config' => ['infer_pure_methods' => true] is set.

• Allow list<X> to cast to array{0:X, 1?:X} (#3390)

• Speed up computing line numbers of diagnostics in the polyfill/fallback parser when there are multiple diagnostics.

Language Server/Daemon mode:

• Reduce the CPU usage of the language server's main process when the pcntl module is used to fork analysis processes (Unix/Linux).
• Speed up serializing large responses in language server mode (e.g. when a string has an unmatched quote).

Commits

• 96a7b3c Merge pull request #3402 from TysonAndre/release-2.3.1
• 9a68cf9 Release 2.3.1
• 210fa4e Merge pull request #3400 from TysonAndre/speed-up-languageserver
• 82dc25f Speed up language server when serializing many issues
• c84dc7d Merge pull request #3399 from TysonAndre/speed-up-languageserver
• d95e6c0 Make the stream_select timeout positive in plugin
• 6beda21 Speed up the language server: avoid busy loop reading in manager
• ae87c4d Merge pull request #3398 from TysonAndre/fix-slow-line-number-calculation
• d4055b8 Fix slow line number calculation of diagnostics for polyfill parser
• 272ebff Merge pull request #3397 from TysonAndre/debug-signal-handler
• Additional commits viewable in compare view

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