Add particle blend mode "clip" (#15444)

This lets modders avoid alpha blending rendering bugs as well as potential (future) performance issues.
The appropriate blend modes are also used for node dig particles.

---------

Co-authored-by: sfan5 <sfan5@live.de>

doc/breakages.md

@@ -21,3 +21,4 @@ This list is largely advisory and items may be reevaluated once the time comes.
 * merge `sound` and `sounds` table in itemdef
 * remove `DIR_DELIM` from Lua
 * stop reading initial properties from bare entity def
+* change particle default blend mode to `clip`

doc/lua_api.md

@@ -5657,6 +5657,8 @@ Utilities
       abm_without_neighbors = true,
       -- biomes have a weight parameter (5.11.0)
       biome_weights = true,
+      -- Particles can specify a "clip" blend mode (5.11.0)
+      particle_blend_clip = true,
   }
   ```
 
@@ -11483,6 +11485,14 @@ texture = {
     -- (default) blends transparent pixels with those they are drawn atop
     -- according to the alpha channel of the source texture. useful for
     -- e.g. material objects like rocks, dirt, smoke, or node chunks
+    -- note: there will be rendering bugs when particles interact with
+    -- translucent nodes. particles are also not transparency-sorted
+    -- relative to each other.
+    blend = "clip",
+    -- pixels are either fully opaque or fully transparent,
+    -- depending on whether alpha is greater than or less than 50%
+    -- (just like `use_texture_alpha = "clip"` for nodes).
+    -- you should prefer this if you don't need semi-transparency, as it's faster.
     blend = "add",
     -- adds the value of pixels to those underneath them, modulo the sources
     -- alpha channel. useful for e.g. bright light effects like sparks or fire