Fix cspell failures after Drupal 11.4.5 removed vendor names from the core dictionary

Problem/Motivation

The cspell job reports "Files checked: 486, Issues found: 5 in 2 files". The same job passed on 3.x two days earlier, on the same cspell version (9.8.0), with no change to either of the files it now flags.

The five reported occurrences are:

• README.md and docs/index.md: Codesniffer, in the link text "PHP Codesniffer".
• README.md: mglaman, in the Composer package name "mglaman/drupal-check".
• README.md, twice: codesniffer, in the Composer package name "squizlabs/php_codesniffer".

The cause is a core change rather than a change in this project. Drupal 11.4.5 removed eleven Composer vendor and package names from core/misc/cspell/dictionary.txt: codesniffer, instantiator, jsonlint, mglaman, micheh, myclabs, phpdocumentor, ralouphie, seld, tbachert and theseer. They went as part of #3607061: Don't spellcheck composer.json, which no longer needs them. The last pipeline to install 11.4.4 reported 0 issues; the first to install 11.4.5 reported 5.

Domain still needs two of those words, because its README quotes a fragment of composer.json inside a fenced code block, and cspell does check markdown.

All four maintained branches carry the same lines: 4.x, 3.x, 3.0.x and 2.0.x. None of them had run a branch pipeline since 11.4.5 was published, so the failure was first seen on a merge request pipeline.

The job is allow_failure: true, so the pipeline as a whole still reports success and the failure is easy to miss.

Proposed resolution

Two of the five occurrences are a genuine misspelling and three are correct as written.

• Spell the tool by its own name, PHP CodeSniffer, rather than PHP Codesniffer. cspell splits CodeSniffer into two words it already knows, so this needs no dictionary entry. The same misspelling sits in the Spanish and French copies of the documentation, which _CSPELL_IGNORE_PATHS keeps cspell away from, and it is corrected there too.
• Add codesniffer and mglaman to .cspell-project-words.txt, for the three occurrences that are Composer package names and cannot be spelled any other way. On 2.0.x that file is not in alphabetical order, so the two words are appended rather than inserted, which keeps the diff to two lines.

Remaining tasks

• Review and merge the merge request against 4.x, then the 3.x, 3.0.x and 2.0.x backports.

User interface changes

None.

API changes

None.

Data model changes

None.

AI-Generated: Yes (Claude Code was used to help draft this issue summary and to write the change on the merge requests. The change was checked with cspell 9.8.0 against the Drupal 11.4.5 dictionaries before posting.)