[Merged by Bors] - chore(data/real/ennreal): adjust form of to_real_pos_iff
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We have a principle (which may not have been crystallized at the time of writing of `data/real/ennreal`) that hypotheses of lemmas should contain the weak form `a ≠ ∞`, while conclusions should report the strong form `a < ∞`, and also the same for `a ≠ 0`, `0 < a`.
In the case of the existing lemma
```lean
lemma to_real_pos_iff : 0 < a.to_real ↔ (0 < a ∧ a ≠ ∞):=
```
it's not clear whether the RHS of the iff should count as a hypothesis or a conclusion. So I have rewritten to provide two forms,
```lean
lemma to_real_pos_iff : 0 < a.to_real ↔ (0 < a ∧ a < ∞):=
lemma to_real_pos {a : ℝ≥0∞} (ha₀ : a ≠ 0) (ha_top : a ≠ ∞) : 0 < a.to_real :=
```
Having both versions available shortens many proofs slightly.
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to_real_pos_iffto_real_pos_iff
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We have a principle (which may not have been crystallized at the time of writing of `data/real/ennreal`) that hypotheses of lemmas should contain the weak form `a ≠ ∞`, while conclusions should report the strong form `a < ∞`, and also the same for `a ≠ 0`, `0 < a`.
In the case of the existing lemma
```lean
lemma to_real_pos_iff : 0 < a.to_real ↔ (0 < a ∧ a ≠ ∞):=
```
it's not clear whether the RHS of the iff should count as a hypothesis or a conclusion. So I have rewritten to provide two forms,
```lean
lemma to_real_pos_iff : 0 < a.to_real ↔ (0 < a ∧ a < ∞):=
lemma to_real_pos {a : ℝ≥0∞} (ha₀ : a ≠ 0) (ha_top : a ≠ ∞) : 0 < a.to_real :=
```
Having both versions available shortens many proofs slightly.
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We have a principle (which may not have been crystallized at the time of writing of
data/real/ennreal) that hypotheses of lemmas should contain the weak forma ≠ ∞, while conclusions should report the strong forma < ∞, and also the same fora ≠ 0,0 < a.In the case of the existing lemma
it's not clear whether the RHS of the iff should count as a hypothesis or a conclusion. So I have rewritten to provide two forms,
Having both versions available shortens many proofs slightly.