Move hints on source files to wiki

Now found at https://collaborating.tuhh.de/m21/public/wiki/-/wikis/Version-Control#hints

README.md

@@ -17,39 +17,6 @@ This very README is also made available for [download as a PDF](https://collabor
 
 ## Appendix
 
-### Hints for source files
-
-These are valid not only for LaTeX files, but most text-based source files:
-
-- For the love of God, use `UTF-8` (and *only* `UTF-8`, not [anything higher](https://news.ycombinator.com/item?id=26737049))
- for text encoding.
- Stop using `Windows 1252`, `Latin` etc.
- Existing files can be easily updated to UTF-8 without much danger for regression
- (*i.e.*, introducing errors).
-- Put each sentence, or even part of a sentence, and each instruction onto its own line.
- This is very important to `diff` files properly, aka `git diff`.
- Generally, [keep lines short](https://tex.stackexchange.com/q/325505/120853).
-- In a similar vein, use indentation appropriately. Indent using **4 spaces**.
- There are schools of thought that advocate two spaces, or also one tab.
- Ultimately, that does not really matter.
- 'Four spaces' just seems to generally win the fight for a common coding style,
- bringing us to the next point.
-- **Be consistent**. Even if you pull your own custom stuff, at least be consistent in doing so.
- This makes things predictable, the code will be easier to read, and also more easily
- changed programmatically.
- GNU/Linux and by extension Windows using
- [Windows Subsystem for Linux](https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux)
- has a very wide range of tools that make search, and search-and-replace, and various other
- operations for plain text files easy.
- The same is true for similar tools in IDEs.
- However, if the text is scattered and the style was mangled and fragmented into various
- sub-styles, this becomes very hard.
- For example, one person might use `$<math>$` for inline-LaTeX math, another the
- ([preferred](https://tex.stackexchange.com/q/510/120853)) `\(<math>\)` style.
- Suddenly, you would have to search for both versions to find all inline-math.
- So stay consistent. If you work on pre-existing documents, use the established style.
- If you change it, change it fully, and not just for newly added work.
-
 ### Hints on Fonts
 
 We use beautiful, capable fonts based on