Extended side effect error messages (#18418)

* Extended side effect error messages

* Applied feedback:
- refactored `markSideEffect`
- refactored string interpolations
- single message
- skip diagnostics in `system.compiles` context

Other:
- started a test of diagnostic messages

[ci skip] Tests aren't updated yet because messaging isn't nailed down.

* - Added hints of where for side effect call locations.
- Tried to clarify the reasons.

* fix tests

* Applied PR review feedback:
  - moved collection of side effects from TSym to TContext
  - used pragma shorthand form `.sideEffect` and `.noSideEffect` in messages
  - added leading '>' to structured messages for readability
  - changed `sempass2.markSideEffect` to a proc
  - replaced `system.echo` in the test to make the test compatible with Windows

* Applied NEP1 formatting suggestion

Co-authored-by: quantimnot <quantimnot@users.noreply.github.com>

compiler/semdata.nim

@@ -159,6 +159,7 @@ type
     exportIndirections*: HashSet[(int, int)] # (module.id, symbol.id)
     importModuleMap*: Table[int, int] # (module.id, module.id)
     lastTLineInfo*: TLineInfo
+    sideEffects*: Table[int, seq[(TLineInfo, PSym)]] # symbol.id index
 
 template config*(c: PContext): ConfigRef = c.graph.config