docs: add param'' ice description

README.md

@@ -785,6 +785,7 @@ You may safely assume a given ice works with both plugins and snippets unless ex
 | `trackbinds`   | Shadow but only `bindkey` calls even with `zinit light ...`, i.e. even with investigating disabled (fast loading), to allow `bindmap` to remap the key-binds. The same effect has `zinit light -b ...`, i.e. additional `-b` option to the `light`-subcommand. **Does not work with snippets.**                                                                                                                                                                                                                                                                                                                                                                   |
 | `wrap-track`   | Takes a `;`-separated list of function names that are to be investigated (meaning gathering report and unload data) **once** during execution. It works by wrapping the functions with a investigating-enabling and disabling snippet of code. In summary, `wrap-track` allows to extend the investigating beyond the moment of loading of a plugin. Example use is to `wrap-track` a precmd function of a prompt (like `_p9k_precmd()` of powerlevel10k) or other plugin that _postpones its initialization till the first prompt_ (like e.g.: zsh-autosuggestions). **Does not work with snippets.**                                                            |
 | `reset-prompt` | Reset the prompt after loading the plugin/snippet (by issuing `zle .reset-prompt`). Note: normally it's sufficient to precede the value of `wait''` ice with `!`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+| `param`        | Creates parameters (variables) for the time of loading a plugin only. The variables are separated from their values via `->` or `→`, e.g.:`param'CMD_COMMAND_PATH → ~/cmds; CMD_DIR → $HOME'`. Multiple vars can be created either via separating them by `;` or via multiple `param''` ices. |
 
 ### Order of Execution<a name="order-of-execution"></a>