Cleanup: prefer term "unreliable" over "flaky"

Avoid slang terms, also correct typo.

source/blender/editors/interface/interface_layout.cc

@@ -268,7 +268,7 @@ static int ui_layout_vary_direction(uiLayout *layout)
 
 static bool ui_layout_variable_size(uiLayout *layout)
 {
-  /* Note that this code is probably a bit flaky, we'd probably want to know whether it's
+  /* Note that this code is probably a bit unreliable, we'd probably want to know whether it's
    * variable in X and/or Y, etc. But for now it mimics previous one,
    * with addition of variable flag set for children of grid-flow layouts. */
   return ui_layout_vary_direction(layout) == UI_ITEM_VARY_X || layout->variable_size_;

source/blender/editors/mesh/editmesh_undo.cc

@@ -898,11 +898,11 @@ static void undomesh_free_data(UndoMesh *um)
 #ifdef USE_ARRAY_STORE
 
 #  ifdef USE_ARRAY_STORE_THREAD
-  /* changes this waits is low, but must have finished */
+  /* Chances this waits is low, but must have finished. */
   BLI_task_pool_work_and_wait(um_arraystore.task_pool);
 #  endif
 
-  /* we need to expand so any allocations in custom-data are freed with the mesh */
+  /* We need to expand so any allocations in custom-data are freed with the mesh. */
   um_arraystore_expand(um);
 
   BLI_assert(BLI_findindex(&um_arraystore.local_links, um) != -1);

source/blender/makesdna/DNA_sdna_types.h

@@ -136,7 +136,7 @@ typedef struct SDNA {
 /**
  * The struct index representing type-less bytes buffers.
  *
- * Although code has historically (pre-4.3) be fairly flaky (logically incorrect, see inline
+ * Although code has historically (pre-4.3) be fairly unreliable (logically incorrect, see inline
  * code-comments for #DNA_struct_get_compareflags regarding this), most of read/write blend-file
  * code would assume that the `0` value was raw data, so keep it at this value.
  */

source/blender/python/intern/bpy_interface.cc

@@ -145,7 +145,7 @@ void bpy_context_clear(bContext * /*C*/, const PyGILState_STATE *gilstate)
   }
   else if (py_call_level == 0) {
     /* NOTE: Unfortunately calling classes currently won't store the context.
-     * Can't set nullptr because of this - but this is very flaky still. */
+     * Can't set nullptr because of this - but this is very unreliable still. */
 #if 0
     BPY_context_set(nullptr);
 #endif