[llvm] [BOLT][heatmap] Produce zoomed-out heatmaps (PR #140153)

[Maksim Panchenko via llvm-commits]

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@@ -89,7 +89,12 @@ For the generation, the default bucket size was used with a line size of 128.
 Some useful options are:
 
 ```
--line-size=<uint>   - number of entries per line (default 256)
+-line-size=<uint>   - number of entries per line (default 256).
+                      Use 128 if the heatmap doesn't fit screen horizontally.
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maksfb wrote:

"Use a smaller value if ..."?

https://github.com/llvm/llvm-project/pull/140153