Fix small grammar mistakes in Developer's guide, and User's guide md files.

[sheshtawy]

Just started learning about Parseq, super cool! While reading the wiki, I noticed a few small grammatical mistakes so I figured I'd fix them to improve the reading experience for everyone.

I fixed them all with ChatGPT GPT-4.1 model, and proofread the changes them myself.

https://github.com/sheshtawy/parseq/wiki

[sheshtawy]

I followed this guide to clone the wiki and make the changes https://gist.github.com/omaraboumrad/35654da0a376c57a2e0ab4d92ad0c339