Style `/pgf/decoration/text effects/word ⟨m⟩ letter ⟨n⟩` documented but never called

[mgkurtz]

Brief outline of the bug

The style word ⟨m⟩ letter ⟨n⟩ (e.g. word 1 letter 1) is never actually used (and thus has no effect) although it is documented on page 659 of the 3.1.10 manual. Additionally the style documented as letter ⟨n⟩ is actually called every ⟨n⟩ letter. For my own use case, I could use the character ⟨n⟩ style. So, I have no strong opinion on whether to change the code to reflect the docs or vice versa.

The piece of code calling all the styles is

https://github.com/pgf-tikz/pgf/blob/a63708935f5c2c465b077dcbeb629e0d03cc4c26/tex/generic/pgf/frontendlayer/tikz/libraries/tikzlibrarydecorations.text.code.tex#L430-L451

It seems simple enough to change it, if wanted.

Minimal working example (MWE)

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary {decorations.text}
\begin{document}
\begin{tikzpicture}[decoration={text effects along path,
    text={11 2023},
    text effects/.cd,
        path from text,
        word 2 letter 4/.style={documented but not called},
        letter 1/.style={documented but not called, instead we have},
        every 1 letter/.style={color=blue},
        characters={text along path}}]
\path [decorate] (0,0);
\end{tikzpicture}
\end{document}