Implement '&&' and '||' operators on map

'-' is a valid character for tags.

Commit 03e1c7d (module/network: Add link stats, 2022-04-30) introduced
two new tags for the network module: `ul-speed` and `dl-speed`. These
use the `-` character, that was previously never used in any tag.

We had two options: either change those tags to use `_` instead, or just
accept `-`s as a valid character. Going forward, I can see many people
deciding to name their tags with `-` instead of `_`, so I believe it is
better to just accept it once and for all.

Note that `-` cannot be used as the first character of a tag (e.g.
`-tag1`) since the `-` has a special meaning in `.yml` files. I don't
believe this will happen often, however, and should be easy to both
detect and correct if it does.

CHANGELOG.md

@@ -87,6 +87,20 @@
         ...
   ```
 
+  Note that if `<value>` contains any non-alphanumerical characters,
+  it **must** be surrounded by `""`:
+
+  `State == "very confused!!!"`
+
+  Finally, you can mix and match conditions using the boolean
+  operators `&&` and `||`:
+
+  ```
+  <condition1> && <condition2>
+  <condition1> && (<condition2> || <condition3>) # parenthesis work
+  ~(<condition1> && <condition2>) # '~' can be applied to any condition
+  ```
+
   For a more thorough explanation, see the updated map section in the
   man page for yambar-particles([#137][137] and [#175][175]).