Add tooltip documentation to web request and brush related nodes (#3427)

* Add tooltip documentation to web request, text, and brush nodes

  - Add descriptive tooltips to web request nodes (GET/POST, string/image conversion, resource loading, image decoding)
  - Add tooltip to GPU rasterization node explaining footprint usage
  - Improve text node tooltip with clearer per_glyph_instances parameter explanation
  - Add tooltips to brush stamp generator and blit operations explaining their internal roles
  - Fix typos in tooltip and variable names (it's→its, perview→preview, instnace→instance)

* Fixed 2 issues with previous changes. Reversed order of documentation about per_glyph_instances. Can it be 3 lines?

* Improve post_request node documentation

Change doc comment to describe the node's purpose rather than focusing
only on the "Discard Result" parameter. Now clearly states this is an
HTTP POST operation with optional async behavior.

* Fix post_request documentation error

Corrected doc comment to say "HTTP POST" instead of "HTTP GET" since
this function performs POST requests with binary data.

* Review changes

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/nodes/path-bool/src/lib.rs

@@ -14,7 +14,7 @@ use std::ops::Mul;
 // Import specta so derive macros can find it
 use core_types::specta;
 
-// TODO: Fix boolean ops to work by removing .transform() and .one_instnace_*() calls,
+// TODO: Fix boolean ops to work by removing .transform() and .one_instance_*() calls,
 // TODO: since before we used a Vec of single-row tables and now we use a single table
 // TODO: with multiple rows while still assuming a single row for the boolean operations.