strings: adding micro-optimization for TrimSpace

[Illirgway]

replace for string's end trimming TrimFunc -> TrimRightFunc

strings.TrimSpace string's end trimming should use more specific TrimRightFunc instead of common TrimFunc (because start has already trimmed before)

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[Illirgway]

@googlebot I signed it!

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[gopherbot]

Message from Robert Griesemer:

Patch Set 1: Code-Review-2

(1 comment)

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[gopherbot]

Message from Robert Griesemer:

Patch Set 1: Code-Review-2

(1 comment)

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