Underline old cursor position for better readability. Reusing
`TermCursor` made me confuse the current window many times.
My favorite solution would be an empty box around the position similar
to how terminals do it when focus is lost. But I fear that this is not
possible with a simple highlighting group.
When deleting the match, w:old_cword has to be unset as well. Otherwise
it can happen that it is not properly readded (e.g. when moving from a
word to an empty line and then back to the same word).
When highlighting the current word, check if it is the same as the
currently highlighted one, so that matchdelete and matchadd are not
called unnecessarily.
Use `matchadd` instead of `match` as it has no limit on the number of
highlights.
Also call the function every time the cursor moved instead of only when
holding. This makes it snappier while also keeping the highlight when
moving inside the cword.
Set `nomodified` after reading from standard input. This way the buffer
can be closed without error message.
This will **not** disable modified warnings completely. If the input is
modified after read, vim will reset `modified` (As it should).
Check that the current word under the cursor exists (not empty) before
adding it as match.
Fix the disappearing of the welcome screen after a short time when
opening vim without file as argument.
Step by step I want to restructure the vim files. The approach to
cleanly divide the config by topics works in zsh pretty well, but is too
vague in vim for my liking.
Especially (the very small) functions and autocommands that have the
purpose of setting options or mapping keys or the interplay of multiple
categories together, make it difficult to decide in which file the
snippets should lay.
Apply the following:
1. Switch to `matchadd` as `match` can only be used for **one**
highlight
2. Use an autocommand group for better behaviour when reloading the
vimrc.
3. Use just one pattern as it seems to work always. (Apparently `\%#` is
not matched in normal mode)
As relative line numbers are only really needed in normal mode and in
the current buffer, disable them in insert mode or when the
buffer/window is not focused.
The old `textwidth` value is meant to be subtracted from colorcolumn, to
then add the new one.
Fixes: 41656d28d6 ("vim:autocmd: Reset textwidth value in colorcolumn")
