Use std::min/max instead of hand-rolling the check

clang-tidy check readability-use-std-min-max
Apparently C++ compilers are good enough to optimize this properly
https://stackoverflow.com/questions/15540250/in-c-is-it-better-to-cap-a-value-using-stdmin-or-an-if-branch

Author: joto

src/gen/gen-discrete-isolation.cpp

@@ -113,9 +113,7 @@ FROM {src} WHERE {importance_column} > 0
                 double const dx = coords[m].first - coords[n].first;
                 double const dy = coords[m].second - coords[n].second;
                 double const dist = dx * dx + dy * dy;
-                if (dist < min) {
-                    min = dist;
-                }
+                min = std::min(dist, min);
             }
             data[n].di = std::sqrt(min);
         }

src/geom-box.cpp

@@ -9,25 +9,17 @@
 
 #include "geom-box.hpp"
 
+#include <algorithm>
 #include <variant>
 
 namespace geom {
 
 box_t &box_t::extend(point_t const &point) noexcept
 {
-    if (point.x() < m_min_x) {
-        m_min_x = point.x();
-    }
-    if (point.y() < m_min_y) {
-        m_min_y = point.y();
-    }
-    if (point.x() > m_max_x) {
-        m_max_x = point.x();
-    }
-    if (point.y() > m_max_y) {
-        m_max_y = point.y();
-    }
-
+    m_min_x = std::min(point.x(), m_min_x);
+    m_min_y = std::min(point.y(), m_min_y);
+    m_max_x = std::max(point.x(), m_max_x);
+    m_max_y = std::max(point.y(), m_max_y);
     return *this;
 }
 
@@ -40,18 +32,10 @@ void box_t::extend(point_list_t const &list) noexcept
 
 void box_t::extend(box_t const &box) noexcept
 {
-    if (box.min_x() < m_min_x) {
-        m_min_x = box.min_x();
-    }
-    if (box.min_y() < m_min_y) {
-        m_min_y = box.min_y();
-    }
-    if (box.max_x() > m_max_x) {
-        m_max_x = box.max_x();
-    }
-    if (box.max_y() > m_max_y) {
-        m_max_y = box.max_y();
-    }
+    m_min_x = std::min(box.min_x(), m_min_x);
+    m_min_y = std::min(box.min_y(), m_min_y);
+    m_max_x = std::max(box.max_x(), m_max_x);
+    m_max_y = std::max(box.max_y(), m_max_y);
 }
 
 box_t envelope(geom::nullgeom_t const & /*geom*/) { return box_t{}; }

src/geom-pole-of-inaccessibility.cpp

@@ -90,9 +90,7 @@ bool point_to_ring_distance_squared(point_t point, ring_t const &ring,
 
         double const d =
             point_to_segment_distance_squared(point, a, b, stretch);
-        if (d < *min_dist_squared) {
-            *min_dist_squared = d;
-        }
+        *min_dist_squared = std::min(d, *min_dist_squared);
     }
 
     return inside;
@@ -158,9 +156,7 @@ point_t pole_of_inaccessibility(const polygon_t &polygon, double precision,
 
     double const min_precision =
         std::max(envelope.width(), envelope.height()) / 1000.0;
-    if (min_precision > precision) {
-        precision = min_precision;
-    }
+    precision = std::max(min_precision, precision);
 
     box_t const stretched_envelope{envelope.min_x(), envelope.min_y() * stretch,
                                    envelope.max_x(),